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Watanabe Yasunori
| Faculty of Engineering Civil Engineering Natural Disasters and Adaptation | Professor |
| Center for Natural Hazards Research | Professor |
Researcher basic information
■ Degree■ URL
researchmap URLホームページURL■ Various IDs
J-Global ID■ Research Keywords and Fields
Research Keyword
- 混相流
- 乱流
- 砕波
- 水工水理学
- 気泡
- 減災
- 浮遊砂
- 画像計測
- 水中音
- 海岸工学
- ジェットの分裂
- 砕波乱流モデル
- 固気液混相流
- 海洋科学
- wavelet packet
- 衝撃砕波力
- 気泡音
- Large Eddy Simulation
- 砕波乱流
- 計測工学
- bubble clouds
- 3次元的水粒子軌道
- 斜行渦
- 混入空気
- 高波数遷移
- 3次元的大規模渦
- Stereo PTV
- 3次元大規
- 波浪
- 防災
- Bachelor's degree program, School of Engineering
- Master's degree program, Graduate School of Engineering
- Doctoral (PhD) degree program, Graduate School of Engineering
Research activity information
■ Papers- Dispersive Wave Focusing in Shoaling Water With Currents
Y. Watanabe; T. Davey; D. M. Ingram
Journal of Geophysical Research: Oceans, Mar. 2026
Scientific journal - INTERFEROMETRIC LASER IMAGING MEASUREMENTS OF SIZE-VELOCITY DISTRIBUTIONS OF SEA SPRAY GENERATED THROUGH WAVE BREAKING
渡部靖憲; 兼安芳輝
土木学会論文集(Web), 81, 17, 2025 - SIZE DISTRIBUTIONS OF POLYDISPERSE PARTICLES IN A SETTLING PROCESS
渡部靖憲; 宮崎一聡
土木学会論文集(Web), 81, 17, 2025 - FUTURE CHANGES IN WINTER STORM SURGES INDUCED BY THE EXPLOSIVE CYCLONES PASSING OVER THE OKHOTSK SEA
野村明弘; 猿渡亜由未; 斎藤翔大; 渡部靖憲
土木学会論文集(Web), 81, 17, 2025 - UNCERTAINTY IN SEA SURFACE DRAG COEFFICIENTS OBTAINED BY VARIOUS METHODS IN A WIND-WAVE TANK
大塚淳一; 渡部靖憲
土木学会論文集(Web), 81, 17, 2025 - MEASUREMENT OF 3D SURFACE STRIATION BEHIND BREAKING WAVES BY THE IR STEREO IMAGING
齋藤翔大; 猿渡亜由未; 野村明弘; 渡部靖憲
土木学会論文集(Web), 81, 17, 2025 - Clustering, coalescing and bursting processes in surface bubbles of surfactant water flows
Yasunori Watanabe; Ayumi Saruwatari
Flow, 4, Cambridge University Press (CUP), 14 Oct. 2024
Scientific journal, Breaking waves aerate seawater surfaces and form whitecaps in the open ocean. The aerated surface area, or whitecap coverage, has been used to macroscopically parametrize air–sea momentum and gas exchange. However, the microscopic mechanisms of the generation, evolution and attenuation of surface bubbles in whitecaps remain poorly understood. In this study, we examined the size distributions and size-dependent lifetimes of surface bubbles generated by water sheet entry and air injection on a porous plate during the clustering, coalescing and bursting processes, depending on surfactant concentrations and bubble mobility. Mechanisms of coalescence through film thinning of adjacent bubble walls owing to the inter-bubble attraction and Marangoni forces experimentally described the surfactant-dependent bubble growth, finally achieving bubble bursting, which were statistically characterized in a population balance analysis. Lagrangian bubble lifetimes were described by the Weibull distribution, providing that surfactant in seawater extended the probabilistic survival periods of surface bubbles two times longer than those of clean bubbles. - Disturbance in the Air-Temperature Field Due to Persistent Bubble Bursting on the Water Surface
Shota Saito; Ayumi Saruwatari; Yasunori Watanabe
World Congress on Momentum, Heat and Mass Transfer, Avestia Publishing, Apr. 2024
International conference proceedings - IMPACT OF SEA LEVEL RISE ON TSUNAMI WATER LEVELS
Kazuki YAGISAWA; Koji MITSUNAGA; Watari TAKAHASHI; Junichi OTSUKA; Fuminori KATO; Ayumi SARUWATARI; Yoshimitsu TAJIMA; Nobuhito MORI; Yasunori WATANABE
Japanese Journal of JSCE, 80, 17, n/a, n/a, Japan Society of Civil Engineers, 2024
Scientific journal - LARGE EDDY SIMULATION OF TURBULENT PORE FLOWS IN POROUS STRUCTURES WITH ARMOR BLOCKS UNDER WAVES
Yasunori WATANABE; Yuichiro SUZUKI; Shota SAITO; Ayumi SARUWATARI
Japanese Journal of JSCE, 80, 17, n/a, n/a, Japan Society of Civil Engineers, 2024
Scientific journal - DISTURBANCES IN THE AIR TEMPERATURE FIELD INDUCED BY INTERMITTENT BUBBLE BURSTING AT THE WATER SURFACE
Shota SAITO; Akihiro NOMURA; Ayumi SARUWATARI; Yasunori WATANABE
Japanese Journal of JSCE, 80, 17, n/a, n/a, Japan Society of Civil Engineers, 2024
Scientific journal - Bubble-Turbulence, Bubble-Surface, and Bubble-Bubble Interactions during Bubble Rise onto Free-Surfaces: (Exploring Mechanisms to Form Whitecaps on Breaking Ocean Waves)
WATANABE Yasunori
JAPANESE JOURNAL OF MULTIPHASE FLOW, 37, 3, 300, 307, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, Sep. 2023
Japanese, Breaking waves entrains huge amounts of air bubbles into bulk seawater, which is involved in turbulence produced in splash-up breaking processes. Buoyant bubbles arriving wave surfaces aggregate to form clusters behind the wave front (so-called whitecap). While a series of the bubble dynamics are believed to be relevant to air-sea momentum transfers and gas exchanges, microscopic bubble behaviors on whitecap water surface in wave breaking turbulence have not been understood. This article introduces previous research progress on mechanical interactions between bubble and turbulence in bulk water under breaking waves, interactions of rising bubble with water surface in addition to interactions among bubbles floating on surface resulting in formation of whitecap water. - STABILITY OF BREAKWATERS DUE TO CLIMATE CHANGE AND ADAPTIVE MEASURES
平野誠治; 奈良俊介; 水口陽介; 早川哲也; 本多和彦; 森信人; 渡部靖憲; 木村克俊
土木学会論文集(Web), 79, 18, 2023 - METHOD FOR FUTURE PROJECTION OF CARGO HANDLING OPERATION RATE IN PORTS CONSIDERING CLIMATE CHANGE
佐藤典之; 早川哲也; 岩崎慎介; 大塚淳一; 平野誠治; 本多和彦; 森信人; 渡部靖憲; 木村克俊
土木学会論文集(Web), 79, 17, 2023 - SPECTRAL CHARACTERISTICS OF WHITECAP WAVE CREST LENGTH AND RESIDUAL FOAM FROM SEA SURFACE IMAGE OBSERVATION
渡部靖憲; 南健人; 猿渡亜由未; 馬場康之; 久保輝広; 森信人; 内山雄介; 志村智也; 大塚淳一; 新井田靖郎; 二宮順一
土木学会論文集(Web), 79, 17, 2023 - FEATURES IN AIR-DENSITY FLUCTUATION NEAR THE WATER SURFACE DURING BUBBLE BURSTING
猿渡亜由未; 齋藤翔大; 渡部靖憲
土木学会論文集(Web), 79, 17, 2023 - FUTURE CHANGES IN WINTER EXPLOSIVE CYCLONES PASSING OVER THE JAPAN-SEA AND SEA OF OKHOTSK AND THEIR IMPACT ON MAXIMUM STORM-SURGE LEVELS
野村明弘; 猿渡亜由未; 渡部靖憲
土木学会論文集(Web), 79, 17, 2023 - EFFICIENT ESTIMATION METHOD FOR FUTURE CHANGES IN DESIGN WAVE HEIGHT USING d4PDF
野村明弘; 佐藤典之; 石川浩希; 早川哲也; 岩崎慎介; 大塚淳一; 森信人; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 78, 2, 2022 - VORTICES AND FLOW STRUCTURES UNDER PLANAR FOCUSING WAVE BREAKERS
渡部靖憲; 藤澤蓮; 猿渡亜由未
土木学会論文集 B2(海岸工学)(Web), 78, 2, 2022 - SEPARATION OF THERMAL BOUNDARY LAYER FROM A LEVITATING DROPLET AND ITS EVAPORATION RATE
猿渡亜由未; 小林正法; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 78, 2, 2022 - FUTURE CHANGE IN THE POSSIBLE STORM-SURGE LEVELS INDUCED BY EXPLOSIVE CYCLONES OF THE JAPAN-SEA AND PACIFIC-OCEAN TRAJECTORY TYPES
猿渡亜由未; 今南実; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 78, 2, 2022 - ANALYSIS OF SEA LEVEL RISE IN COASTAL AREAS WITH TECTONIC DISPLACEMENT
NOMURA Akihiro; ISHIKAWA Hiroki; SATO Noriyuki; HAYAKAWA Tetsuya; IWASAKI Shinsuke; OTSUKA Junichi; MORI Nobuhito; WATANABE Yasunori
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 78, 2, I_487, I_492, Japan Society of Civil Engineers, 2022
Japanese, Sea level rise expected during climate changes is one of the important issues in future coastal protection. To estimate the sea level at coast with tectonic activity, the observed sea level records need to be collected with the ground displacement. This paper presents a regression analysis of the sea level rise estimated by tidal records collected with ground level observations along coasts of Hokkaido. The error analysis provides conditions to extract available datasets observed at local sites with tectonic displacements. Future projections of the current estimations are consistent with predictions by the previous climate-ocean models, which ensures appropriate analysis for future sea level rise. - Bubble drag in electrolytically generated microbubble swarms with bubble-vortex interactions
Yasunori Watanabe; Haruhi Oyaizu; Hisashi Satoh; Yasuo Niida
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW, 136, Mar. 2021
English, Scientific journal - A METHOD TO EVALUATE SUPERIMPOSITION TSUNAMI CAUSED BY SUBMARINE LANDSLIDE AND ACTIVE FAULT.
金戸俊道; 木村達人; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 77, 2, 2021 - FBP-BOS法を用いた単一浮遊液滴近傍の密度分布の可視化法
小林 正法; 猿渡 亜由未; 渡部 靖憲
土木学会論文集. B2, 海岸工学 Journal of Japan Society of Civil Engineers. Series B2, Coastal engineering / 土木学会海岸工学委員会 編, 77, 2, 3p, 土木学会, 2021
Japanese - WAVE PACKET FOCUSING UNIFORM CURRENT
WATANABE Yasunori; OGUMA Takashi
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77, 2, I_31, I_36, Japan Society of Civil Engineers, 2021
Japanese, In this study, a theoretical frequency condition to create the focusing wave packet in uniform current is proposed and validated through wave-current experiments. We observed the maximum surface elevation monotonically increase with the current velocity and the highest elevation of six times higher than the initial wave amplitude is recorded at the highest current velocity in the present experimental conditions. We also found the temporal variations of the spectrum width during the focusing process and the nonlinear steep wave form with double harmonic component at the focusing location. - SUBGRID MODEL OF BUBBLE-FOAM-COUPLED TURBULENT FLOW
WATANABE Yasunori; WATANABE Kenta
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77, 2, I_43, I_48, Japan Society of Civil Engineers, 2021
Japanese, In this study, the novel LES-Stochastic model describing bubble rise, bubble-interface interactions, bubble cluster formations, coupled with turbulent fluid motion, has been proposed. The foam model, developed on the basis of the analytical solution of bubble-bubble mechanical interactions by Nicolson (1948), reasonably simulated oscillatory bubble behaviors beneath the interface and formations of the bubble clusters. These processes create additional turbulence near the interface and thus enhance surface renewal, which may contribute material transport between air and water. - A METHOD TO EVALUATE SUPERIMPOSITION TSUNAMI CAUSED BY SUBMARINE LANDSLIDE AND ACTIVE FAULT.
KANETO Toshimichi; KIMURA Tatsuto; WATANABE Yasunori
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77, 2, I_229, I_233, Japan Society of Civil Engineers, 2021
Japanese, Scientific journal, Kaneto et al. proposed a method to evaluate possible future tsunami caused by submarine landslide. However, superposition with tsunami caused by active faults, which is likely to cause submarine landslides, has not been investigated. This study focuses on the distribution of tsunami arrival times within a radius of 100 km from the Kashiwazaki-Kariwa Nuclear Power Station, proposes a method for determining the combination of tsunamis caused by submarine landslides and active fault. In addition, we evaluated the maximum water level due to the superimposed tsunami by the linear addition method of the tsunami numerical simulation and the method by coupled analysis, and it was confirmed that there was no significant difference in the tendency of the analysis results by either method. - Probabilistic analysis of winter storm surges depending on meteorological features of explosive cyclones
Ayumi Saruwatari; Yasunori Watanabe
Proceedings of the Coastal Engineering Conference, 36, 2020, 31 Dec. 2020
International conference proceedings - Three-dimensional antidunes coexisting with alternate bars
Takuya Inoue; Yasunori Watanabe; Toshiki Iwasaki; Junichi Otsuka
EARTH SURFACE PROCESSES AND LANDFORMS, 45, 12, 2897, 2911, Sep. 2020
English, Scientific journal - Wave packet focusing in shallow water
Yasunori Watanabe; Yosuke Tsuda; Ayumi Saruwatari
Coastal Engineering Journal, 62, 2, 336, 349, 02 Apr. 2020, [Peer-reviewed]
English, Scientific journal - A METHOD TO EVALUATE POSSIBLE FUTURE TSUNAMI CAUSED BY SUBMARINE LANDSLIDE.
金戸俊道; 山本和哉; 木場正信; 木村達人; 西愛歩; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 76, 2, 2020 - CLUSTERING, COALESCENCE AND COLLAPSE PROCESS OF RESIDUAL FOAMS ON SURFACTANT WATER SURFACES
渡部靖憲; 野中拓実
土木学会論文集 B2(海岸工学)(Web), 76, 2, 2020 - Formation and collapse of concentric focusing waves in Faraday wave fleld
渡部靖憲; 小嶋亮太
土木学会論文集 B2(海岸工学)(Web), 76, 2, 2020 - MECHANISM TO FORM WIND WAVES VIA AIR-WATER INTERACTIONS IN WIND/OCEAN BOUNDARY LAYERS
渡部靖憲; 土屋裕嵩
土木学会論文集 B2(海岸工学)(Web), 76, 2, 2020 - STABILITY AND BEACH PROTECTION PROPERTY OF THE ROUND GABION REVETMENT
猿渡亜由未; 小林正法; 高須賀啓孝; 小山裕文; 高橋幹夫; 山下孝行; 樋口益盛; 渡部靖憲
土木学会論文集 A2(応用力学)(Web), 76, 2, 2020 - High wave coniditions due to typhoons measured at an offshore observation tower
Yasuyuki Baba; Teruhiro Kubo; Nobuhito Mori; Yasunori Watanabe; Tomohito Yamada; Ayumi Saruwatari; Junichi Otsuka; Yusuke Uchiyama; Junichi Ninomiya; Tomoya Shimura
22nd Congress of the International Association for Hydro-Environment Engineering and Research-Asia Pacific Division, IAHR-APD 2020: "Creating Resilience to Water-Related Challenges", 2020
International conference proceedings - Performance of gabion revetments for stabilizing beach profile
Ayumi Saruwatari; Masanori Kobayashi; Nobutaka Takasuka; Hirofumi Koyama; Mikio Takahashi; Yasunori Watanabe
22nd Congress of the International Association for Hydro-Environment Engineering and Research-Asia Pacific Division, IAHR-APD 2020: "Creating Resilience to Water-Related Challenges", 2020
International conference proceedings - Laboratory experiments of bubble formations and behaviors in surfactant seawater
Takumi Nonaka; Yasunori Watanabe
22nd Congress of the International Association for Hydro-Environment Engineering and Research-Asia Pacific Division, IAHR-APD 2020: "Creating Resilience to Water-Related Challenges", 2020
International conference proceedings - Probabilistic assessment of storm surge potential due to explosive cyclogenesis in the northwest Pacific region
A. Saruwatari; K. Fukuhara; Y. Watanabe
Coastal Engineering Journal, 61, 4, 520, 534, 02 Oct. 2019, [Peer-reviewed]
English, Scientific journal - APPLICABILITY OF MEASUREMENT OF AIR NEGATIVE IONS IN ESTIMATING PRODUCTION RATE OF SEA SPRAY
SARUWATARI Ayumi; ISHIMI Shota; WATANABE Yasunori
Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 75, 2, I_531, I_537, Japan Society of Civil Engineers, 2019, [Peer-reviewed]
Japanese,This study is to examine applicability of air-ion concentration to improve estimation accyracy of production rate of sea spray from the ocean. Concentration of air negative ions that is know to be influenced by generation of tiny sea spray was found to response to variation in production of film droplets induced by bubble bursting on water surface from our laboratory experiment. Also, concentration of air negative ions was observed in three ocean areas along Hokkaido, Japan; Sea of Japan, Sea of Okhotsk and the Pacific Ocean. The ion concentration was found to be correlated with the wind speed, wave height and whitecap ratio, all of which have been used as a model parameter of Sea Spray Generation Functions, indicating possibility of using air-ion concentration to accurate estimation of sea spray production.
- HEAT TRANSFER INTO OCEAN WATER DURING GROWTH OF WIND WAVES
渡部靖憲; 杉村一直; 山下賢人; 猿渡亜由未
土木学会論文集 B2(海岸工学)(Web), 75, 2, I_49, 54, 土木学会, 2019, [Peer-reviewed]
Japanese - REVISING WAVE INDUCED TURBULENT MIXING AND ITS IMPACT ON TROPICAL CYCLONE
高木雅史; 森信人; 二宮順一; 志村智也; 内山雄介; 馬場康之; 水谷英朗; 久保輝広; 渡部靖憲; 大塚淳一; 山田朋人; 猿渡亜由未
土木学会論文集 B2(海岸工学)(Web), 75, 2, I_61, 66, 土木学会, 2019, [Peer-reviewed]
Japanese - ULTRASONIC BACKSCATTER MODEL ESTIMATING HEAT TRANSFER BY BUBBLE CLOUD IN THE OCEAN
猿渡亜由未; 大塚淳一; 馬場康之; 久保輝広; 水谷英朗; 志村智也; 二宮順一; 山田朋人; 内山雄介; 森信人; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 75, 2, I_67, 72, 土木学会, 2019, [Peer-reviewed]
Japanese - HIGH WAVES DUE TO TYPHOONS IN THE SUMMER OF 2018 OBSERVED AT AN OBSERVATION TOWER
馬場 康之; 久保 輝広; 森 信人; 渡部 靖憲; 山田 朋人; 猿渡 亜由未; 大塚 淳一; 内山 雄介; 二宮 順一
土木学会論文集. B2, 海岸工学 Journal of Japan Society of Civil Engineers. 土木学会海岸工学委員会 編, 75, 2, I_271, 276, 土木学会, 2019, [Peer-reviewed]
Japanese - RAINFALL OBSERVATION IN THE COASTAL AREA WITH OPTICAL DISDROMETERS IN THE SUMMER OF 2013
岡地寛季; 山田朋人; 渡部靖憲; 猿渡亜由未; 大塚淳一; 森信人; 馬場康之; 久保輝広; 二宮順一; 内山雄介; 水谷英郎
土木学会論文集 G(環境)(Web), 27, 5, 41, 46, 土木学会, 2019, [Peer-reviewed]
Japanese - Numerical experiments on effect of river mouth morphology on tsunami behavior in rivers
Yuta Mitobe; Hitoshi Tanaka; Kazuya Watanabe; Neetu Tiwari; Yasunori Watanabe
Coastal Engineering Journal, 60, 4, 516, 531, 02 Oct. 2018, [Peer-reviewed]
English, Scientific journal - Oxygen transfer from bubble-plumes
Yasuo Niida; Yasunori Watanabe
Physics of Fluids, 30, 10, 01 Oct. 2018, [Peer-reviewed]
English, Scientific journal - Effects of rain droplets and sea sprays on the momentum and latent heat fluxes
Hiroki Okachi; Tomohito J. Yamada; Yasunori Watanabe; Junichi Ohtsuka
Proceedings - International Association for Hydro-Environment Engineering and Research (IAHR)-Asia Pacific Division (APD) Congress: Multi-Perspective Water for Sustainable Development, IAHR-APD 2018, 1, 493, 502, 01 Sep. 2018, [Peer-reviewed]
International conference proceedings - DEVELOPMENT OF INTERNAL WAVES NEAR THE TSUGARU STRAIT ASSOCIATED WITH A STORM EVENT
猿渡亜由未; 足立天翔; 宮武誠; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 74, 2, 2018 - Air-water interface transport and surface renewal under impacting droplets
門脇壮健; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 74, 2, 2018 - INFLUENCE OF SEA SPRAY AND RAINDROP ON THE MOMENTUM EXCHANGE AT AIR-SEA INTERFACE
岡地寛季; 山田朋人; 渡部靖憲
土木学会論文集 B1(水工学)(Web), 74, 4, 2018 - AIR-FLOW OVER WIND WAVES AND SEA-SURFACE DRAG COEFFICIENT UNDER VERY STRONG WIND
山下賢人; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 74, 2, 2018 - High-resolution tsunami-bedload coupled computation in AMR environment
Yasunori Watanabe; Yuta Mitobe; Hitoshi Tanaka; Kazuya Watanabe
Proceedings of the Coastal Engineering Conference, 36, 2018, 2018, [Peer-reviewed]
International conference proceedings - Laboratory observations of dissolved carbon dioxide transport under regular breaking waves
Junichi Otsuka; Yasunori Watanabe
Proceedings of the Coastal Engineering Conference, 36, 2018, 2018, [Peer-reviewed]
International conference proceedings - DEVELOPMENT OF INTERNAL WAVES NEAR THE TSUGARU STRAIT ASSOCIATED WITH A STORM EVENT
SARUWATARI Ayumi; ADACHI Amato; MIYATAKE Makoto; WATANABE Yasunori
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 74, 2, I_661, I_666, 公益社団法人 土木学会, 2018, [Peer-reviewed]
Japanese - Turbulent Boundary Layer Flows over Progressive Water Waves
K. Yamashita; Y. Watanabe; A. Saruwatari
Proc. iCFM, 2018
English, International conference proceedings - Phase-Field computation of drop impacts
S. Kadowaki; Y. Watanabe; A. Saruwatari
Proc. iCFM, 2018
International conference proceedings - Sediment advection and diffusion by obliquely descending eddies
Ayumi Saruwatari; Junichi Otsuka; Yasunori Watanabe
Proceedings of the Coastal Engineering Conference, 36, 2018, 2018, [Peer-reviewed]
English, International conference proceedings - SEASONAL VARIABILITY OF WATER EXCHANGE AT THE ENTRANCE OF A SEMI-ENCLOSE BAY AND ITS UNDERLYING MECHANISMS
岡田 信瑛; 内山 雄介; 多田 拓晃; 遠藤 颯; 馬場 康之; 水谷 英朗; 久保 輝広; 森 信人; 渡部 靖憲; 大塚 淳一; 山田 朋人; 猿渡 亜由未; 二宮 順一
土木学会論文集. B2, 海岸工学 Journal of Japan Society of Civil Engineers. 土木学会海岸工学委員会 編, 74, 2, I_667, 672, 土木学会, 2018
Japanese - RESPONSE OF THE OCEAN SURFACE LAYER WITH BREAKING WAVES IN FETCH-LIMITED WIND CONDITIONS
猿渡 亜由未; 坂川 諒太; 大塚 淳一; 馬場 康之; 久保 輝広; 水谷 英朗; 二宮 順一; 山田 朋人; 内山 雄介; 森 信人; 渡部 靖憲
土木学会論文集. B2, 海岸工学 Journal of Japan Society of Civil Engineers. 土木学会海岸工学委員会 編, 74, 2, I_67, 72, 土木学会, 2018
Japanese - Numerical experiments on effect of river mouth morphology on tsunami behavior in rivers
Mitobe Yuta; Tanaka Hitoshi; Watanabe Kazuya; Tiwari Neetu; Watanabe Yasunori
COASTAL ENGINEERING JOURNAL, 60, 4, 516, 531, 2018, [Peer-reviewed] - Vortex-induced suspension of sediment in the surf zone
Junichi Otsuka; Ayumi Saruwatari; Yasunori Watanabe
Advances in Water Resources, 110, 59, 76, Dec. 2017, [Peer-reviewed]
English, Scientific journal - Vortex-induced suspension of sediment in the surf zone
Junichi Otsuka; Ayumi Saruwatari; Yasunori Watanabe
ADVANCES IN WATER RESOURCES, 110, 59, 76, Dec. 2017, [Peer-reviewed]
English, Scientific journal - Tide deviation characteristics in Uchiura Bay modeled on Typhoon Lionlock (2016)
南翔; 工藤圭太; 八木澤一城; 橋本孝治; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 73, 2, 2017 - CHARACTERISTICS OF COLLISION FORCE AND ITS SIMPLE EVALUATION FORMULA FOR BRITTLE MATERIALS SUCH AS SEA ICE BASE ON MEDIUM-SCALE EXPERIMENTS AND NUMERICAL CALCULATIONS
木岡信治; 遠藤強; 竹内貴弘; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 73, 2, 2017 - SEA SURFACE SHEAR LAYER AND AIR-WATER MOMENTUM TRANSFER IN THE INITIAL STAGE OF WIND-WAVE GENERATION
渡部靖憲; 杉村一直
土木学会論文集 B2(海岸工学)(Web), 73, 2, 2017 - THE CHARACTERISTICS ON WAVE OVERTOPPING IN TOMAMAE FISHING PORT
水戸佳祐; 八木澤一城; 佐野朝昭; 橋本孝治; 本田達也; 本山賢司; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 73, 2, 2017 - Research about a Storm surge in cold region : Case in Nemuro harbor
吉田 徹; 橋本 茂樹; 時沢 武史; 小田 玲司; 猿渡 亜由未; 渡部 靖憲
寒地技術論文・報告集 寒地技術シンポジウム, 33, 229, 234, 北海道開発技術センター, 2017
Japanese - CHARACTERISTICS OF COLLISION FORCE AND ITS SIMPLE EVALUATION FORMULA FOR BRITTLE MATERIALS SUCH AS SEA ICE BASE ON MEDIUM-SCALE EXPERIMENTS AND NUMERICAL CALCULATIONS
KIOKA Shinji; ENDO Tsutomu; TAKEUCHI Takahiro; WATANABE Yasunori
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 73, 2, I_973, I_978, Japan Society of Civil Engineers, 2017, [Peer-reviewed]
Japanese, Medium-scale experiments and numerical calculations by DEM were performed to examine the dynamic fracture of sea ice masses by their collisions with prismatic structures along with a flat plane and to propose a simple method to estimate the collision force. It was confirmed that the actual collision under ideal conditions such as complete surface to surface contact by ice with uniform material properties would be very rare, and that the experimental results were consequently scattered. The maximum collision forces by the numerical calculations agreed with a theoretical simple formula for a flat-plane structure whether ice fracture occurred or not. We proposed a simple method to estimate the forces with structures with arbitrary size base on the theoretical formula and the experimental results including DEM/FEM. - SEA SURFACE SHEAR LAYER AND AIR-WATER MOMENTUM TRANSFER IN THE INITIAL STAGE OF WIND-WAVE GENERATION
WATANABE Yasunori; SUGIMURA Kazunao
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 73, 2, I_73, I_78, Japan Society of Civil Engineers, 2017, [Peer-reviewed]
Japanese, This paper presents mechanical features of transitional air-water momentum and energy transfers in initial growing wind waves on the basis of the fluid flow statistics observed in wind-wave tunnel experiments. In the initial waves with short fetch, superpositions of capillary waves on the crest of gravity waves generate significant vorticity and transport it downward, resulting in a thick momentum boundary layer containing organized vortices. As the capillaries attenuate in growing wind-driven current via wave-current interaction, with increase of fetch, vorticity generation also attenuate and thus the thickness of the boundary layer decrease. - THE CHARACTERISTICS ON WAVE OVERTOPPING IN TOMAMAE FISHING PORT
MIZUTO Keisuke; YAGISAWA Kazuki; SANO Tomoaki; HASHIMOTO Koji; HONDA Tatsuya; MOTOYAMA Kenji; WATANABE Yasunori
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 73, 2, I_829, I_834, Japan Society of Civil Engineers, 2017, [Peer-reviewed]
Japanese, Tomamae fishing port is hindered the use of port areas and boat moorings behind the western outskirts by the overtopping waves, especially in winter season. However, in this port, comprehensive viewpoints including the formation of overtopping waves and environmental conditions which generate wave overtopping have not been revealed yet. In this study, in order to understand the wave overtopping in the western outskirts, field observation using a web camera was conducted, and various analyzes were made on the relationship between the overtopping wave phenomenon captured by the web camera and environmental conditions, including wave, wind and tidal level. Furthermore, conducting numerical simulation with CADMAS-SURF, on-site characteristics on wave overtopping were revealed. - Tide deviation characteristics in Uchiura Bay modeled on Typhoon Lionlock (2016)
MINAMI Sho; KUDOU Keita; YAGISAWA Kazuki; HASHIMOTO Koji; WATANABE Yasunori
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 73, 2, I_205, I_210, Japan Society of Civil Engineers, 2017, [Peer-reviewed]
Japanese, Typhoon Lionlock (2016) followed a complicated route that was different from the conventional typhoon. Lionlock moved northwest of the Tohoku region, and proceeded to the Sea of Japan . the typhoon caused large fishery damage due to windward flow and strong winds in Hokkaido's Uchura Bay.it is very important to calcurate tide deviation occured by typhoon that followed a characteristic course. Therefore, in this study, numerical experiments using a typhoon model and nonlinear longwave model were performed. Using the Lionlock typhoon as a model, we calculated the storm surge of eight possible tracks, clarified the occurrence characteristics of the tide deviation in Uchiura Bay and estimated the damages along each track. Further, we made calculations for creating a tidal flooded immersion area map (Ministry of Land, Infrastructure and Transport), and obtained knowledge on measures to use against storm surges along the coast of Uchiura Bay in the future. - UNSTABLE ROTATIONAL FLOW AROUND AN AIR TUBE
WATANABE Yasunori; SUZUKI Atsuki
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 73, 2, I_91, I_96, Japan Society of Civil Engineers, 2017, [Peer-reviewed]
Japanese, A novel experiment of free-surface deformation in a rotating circular cylinder is proposed in this study, which physically models an air-tube fragment observed in a plunging wave breaking. It is found during the experiment that the fragment is induced by unstable anti-symmetric rotating flows around air-tube affected by centrifugal force, surface tension, buoyancy and drag force. Overall features of the fragment wave-number and critical rotation frequency can be described in terms of Froude and Weber numbers. - A new approach to numerical modeling of tsunami considering unsteady boundary layer develpment
Hitoshi Tanaka; Yuta Mitobe; Neetu Tiwari; Kazuya Watanabe; Yasunori Watanabe
Proceedings of The 3rd International Conference on Coastal Zone Engineering and Management in the Middle East (Arabian Coast 2016) (Nov 20-23, Debai UAE) (Keynote lecture), 22 Nov. 2016, [Peer-reviewed], [Invited]
English, International conference proceedings - AMR-CIP computational framework for tsunami run-up on high resolution topography
Yasunori Watanabe; Hitoshi Tanaka; Yuta Mitobe; Kazuya Watanabe
Journal of JSCE B2 (Coastal Eng), B2-72, 2, I_283, I_288, 17 Nov. 2016, [Peer-reviewed]
Japanese, Scientific journal - Numerical experiment on water level change in river with different magnitude of tsunamis
Yuta Mitobe; Kazuya Watanabe; Hitoshi Tanaka; Neetu Tiwari; Yasunori Watanabe
Journal of JSCE B2 (Coastal Eng), B2-72, 2, I_259, I_264, 17 Nov. 2016, [Peer-reviewed]
Japanese, Scientific journal - Upper-ocean Dynamic Water-exchange at the Entrance of a Semi-enclose Bay under Stratified and unstratified Conditions
内山 雄介; 吉木 智軌; 多田 拓晃; 馬場 康之; 水谷; 久保 輝広; 森 信人; 猿渡 亜由未; 大塚 淳一; 二宮 順一; 渡部 靖憲; 山田 朋人
土木学会論文集B4(海岸工学) = Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 72, 2, I_493, I_498, 土木学会 = Japan Society of Civil Engineers, 15 Nov. 2016, [Peer-reviewed]
Japanese, For rigorious description of upper ocean dynamics and resultant volume transport at the mouth of Tanabe Bay, Wakayama, Japan, a comprehensive field campaign was conducted from summer to fall of 2015. The vertical structure of transient dynamics in the surface boundary layer and consequent water exchange at the mouth are characterized by high-frequency variability peaked at around the semi-diurnal period as well as in the lower-frequency subtidal band centered at 3 day period, consistent with the previous modeling study. A spectral coherence analysis indicates that near-surface currents are mainly driven by wind stress peaked at the diurnal frequency, whereas subsurface currents fluctuate rather by semi-diurnal internal tides. The upper ocean cools down gradually, corresponding to seasonal transition from summer to fall condition. However, an abrupt cooling event is observed albeit in a calm local forcing condition where an offshore subtidal cold water intrusion induced remotely by the fluctuating Kuroshio path plays an essential role. - A Study on Destruction of the Rmocline and Vertical Mixing Based on Field Measurement
久保 慎也; 二宮 順一; 森 信人; 馬場 康之; 水谷 英朗; 久保 輝広; 内山 雄介; 渡部 靖憲; 山田 朋人; 大塚 淳一; 猿渡 亜由未
土木学会論文集B2(海岸工学) = Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 72, 2, I_487, I_492, 土木学会 = Japan Society of Civil Engineers, 15 Nov. 2016, [Peer-reviewed]
Japanese, This study focuses on the process of thermocline's destruction and reformation during typhoons using field observation data. The thermocline has a large effect on the circulation and would be a factor to make water worse. Therefore, it is necessary to understand its process deeply. In this study, the stability of density stratification was evaluated based on the Brant-Vaisala frequency and the Richardson number. The results suggested that high wave destroyed the stratification and high wind mixed ocean water vertically more energetically during stratified season. On the other hand, is was found that stratification was unstable regardless of typhoon intensity during unstratified season. Moreover, the characteristics of water-mass were evaluated on the TS diagram during unstratified season. - Numerical simulation of tsunami river runup by Simultaneous Coupling Method (SCM)
Yuta Mitobe; Neetu Tiwari; Kazuya Watanabe; Hitoshi Tanaka; Yasunori Watanabe
Journal of JSCE B2 (Coastal Eng), B2-72, 2, I_259, I_264, Nov. 2016, [Peer-reviewed]
Japanese, Scientific journal - Size distributions of sprays produced by violent wave impacts on vertical sea walls
Y. Watanabe; D. M. Ingram
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 472, 2194, 20160423, 20160423, The Royal Society, 01 Oct. 2016, [Peer-reviewed]
International conference proceedings - The international river interface cooperative: Public domain flow and morphodynamics software for education and applications
Jonathan M. Nelson; Yasuyuki Shimizu; Takaaki Abe; Kazutake Asahi; Mineyuki Gamou; Takuya Inoue; Toshiki Iwasaki; Takaharu Kakinuma; Satomi Kawamura; Ichiro Kimura; Tomoko Kyuka; Richard R. McDonald; Mohamed Nabi; Makoto Nakatsugawa; Francisco R. Simões; Hiroshi Takebayashi; Yasunori Watanabe
Advances in Water Resources, 93, 62, 74, 01 Jul. 2016, [Peer-reviewed]
English, Scientific journal - Study on estimation of damages caused by sea ice floes driven by run-up tsunami-Physical and computational experiments of fracture, behavior and run-up of sea ice-
KIOKA Shinji; TAKEUCHI Takahiro; WATANABE Yasunori
Proceedings of the International Symposium on Okhotsk Sea & Sea Ice, 31st, 270‐273, 20 Feb. 2016
English - 遡上波先端モデルの3次元LESへの導入と都市型津波浸水過程への適用
渡部靖憲; 佐々木理沙; 小柳津遥陽; 牧田拓也; 森岡晃一; 猿渡亜由未
土木学会論文集 B2(海岸工学)(Web), 72, 2, 2016 - 半閉鎖性海域湾口部における成層期および成層崩壊期の流動構造と海水交換について
内山雄介; 吉木智軌; 多田拓晃; 馬場康之; 水谷英朗; 久保輝広; 森信人; 猿渡亜由未; 大塚淳一; 二宮順一; 渡部靖憲; 山田朋人
土木学会論文集 B2(海岸工学)(Web), 72, 2, 2016 - 現地観測に基づく水温躍層の破壊と鉛直混合に関する研究
久保慎也; 二宮順一; 森信人; 馬場康之; 水谷英朗; 久保輝広; 内山雄介; 渡部靖憲; 山田朋人; 大塚淳一; 猿渡亜由未
土木学会論文集 B2(海岸工学)(Web), 72, 2, 2016 - STATISTICAL RISK ANALYSIS OF STORM SURGE BY AN EXTRATROPICAL CYCLONE IN WINTER
SARUWATARI Ayumi; TAKEE Toshihiro; WATANABE Yasunori
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 72, 2, I_247, I_252, 公益社団法人 土木学会, 2016, [Peer-reviewed]
Japanese, Explosively developing extratropical cyclones are becoming one of the important factors to cause a storm surge in winter. This study statistically evaluates risk of storm surge based on 3D flow fields under developing storm surge computed for various meteorological conditions. Vertical structure of the flow in the Nemuro Bay driven by the strong wind and wind-induced surface gradient showed characteristics different from that in the open ocean forming a typical Ekman spiral. Surge height and event duration are sensitive to the cyclone trajectory. The results of this study also shows the highest surge level in the Nemuro Bay had a risk to increase more than 1.5 times as high as the highest surge of the storm event in 2014. - IN SITU MEASUREMENTS OF ATMOSPHERIC AEROSOL OVER THE OCEAN
SARUWATARI Ayumi; NINOMIYA Junichi; WATANABE Yasunori; YAMADA Tomohito; OTSUKA Junichi; BABA Yasuyuki; MIZUTANI Hideaki; KUBO Teruhiro; UCHIYAMA Yusuke; MORI Nobuhito
Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 72, 2, I_537, I_547, Japan Society of Civil Engineers, 2016, [Peer-reviewed]
Japanese, Sea spray is one of the important factors to affect weather conditions over the ocean in terms of constituting an aerosol as well as determining air-sea transport of heat, moisture and momentum. The final goal of this study is to explain the relationship between sea-spray generation and conditions of the atmosphere and ocean for a more accurate prediction of the amount of sea spray. This study conducted three-year field observations of atmospheric aerosol at an offshore observatory in Tanabe Bay, Wakayama. Large-scale (> 100 km) distribution of atmospheric aerosol was found to dominate the concentration of the observed aerosol less than 1 μm in normal weather conditions. During storm events with strong winds from the Pacific Ocean, however, the observed concentration monotonically increased with the wind speed, which is considered to be a result of the increase in oceanic aerosol derived from sea spray. - Application of a moving contact model for run-up waves to urban flooding process
WATANABE Yasunori; SASAKI Risa; OYAIZU Haruhi; MAKITA Takuya; MORIOKA Koichi; SARUWATARI Ayumi
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 72, 2, I_67, I_72, Japan Society of Civil Engineers, 2016, [Peer-reviewed]
Japanese, Scientific journal, This paper presents the boundary condition model, based on empirical contact angle model, for free-surfaces on moving contact lines of run-up waves. The inundation process on an urban topographic model composed of streets and impermeable blocks, which models urban floods observed in Kamaishi city affected by the 2011 Tohoku tsunami, was computed in this study. We find unsteady bores are consecutively formed under steady overflows from a tide wall and propagate along streets, which causes unsteady wave forces on urban buildings for long time. - MECHANISMS TO DEVELOP HIGH WAVES INDUCED BY AN EXPLOSIVE CYCLOGENESIS OVER THE JAPAN SEA
猿渡亜由未; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 71, 2, 1537, 1542, Nov. 2015, [Peer-reviewed]
Japanese, Scientific journal - Transverse instabilities of ascending planar jets formed by wave impacts on vertical walls
Y. Watanabe; D. M. Ingram
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 471, 2182, 08 Oct. 2015, [Peer-reviewed]
International conference proceedings - Report on the 2014 Winter Cyclone Storm Surge in Nemuro, Japan
Ayumi Saruwatari; Adriano Coutinho De Lima; Masaya Kato; Osamu Nikawa; Yasunori Watanabe
Coastal Engineering Journal, 57, 3, 19 Sep. 2015, [Peer-reviewed]
Scientific journal - Report on the 2014 Winter Cyclone Storm Surge in Nemuro, Japan
Ayumi Saruwatari; Adriano Coutinho de Lima; Masaya Kato; Osamu Nikawa; Yasunori Watanabe
COASTAL ENGINEERING JOURNAL, 57, 3, 1550014.1-1550014.14, Sep. 2015, [Peer-reviewed]
English, Scientific journal - Characteristic time, length and velocity scales of transverse flows in the surf zone
Junichi Otsuka; Yasunori Watanabe
Coastal Engineering Journal, 57, 2, 20 Jun. 2015, [Peer-reviewed]
Scientific journal - Characteristic Time, Length and Velocity Scales of Transverse Flows in the Surf Zone
Junichi Otsuka; Yasunori Watanabe
COASTAL ENGINEERING JOURNAL, 57, 2, 1550006.1-1550006.22, Jun. 2015, [Peer-reviewed]
English, Scientific journal - Kinetic and geometric properties of run-up wave fronts induced by dam-break flows
WATANABE Yasunori; OSHIMA Yuki
PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 71, 2, I_43, I_48, Japan Society of Civil Engineers, 2015
Japanese, In this study, imaging experiments for measuring free-surface shapes of run-up dambreak waves and fluid velocity distributions on the basis of Laser-Induced Fluorescence (LIF) and Super-Resolution Particle Imaging Velocimetry (SRPIV) were performed with aim to identify kinetic features of the run-up flows depending on slop angles. Organized patterns of the rotational shear flows are found to be formed in the bottom and surface boundary layers behind the wave front, which provides mechanical effects to provide typical blob-like surface shape in the wave front as well as wavy surface form behind it. - Unstable behaviours of cavities formed by steady planar jets on still water
WATANABE Yasunori; MAKITA Takuya; OYAIZU Haruhi
PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 71, 2, I_37, I_42, Japan Society of Civil Engineers, 2015
Japanese, In this study, local behaviors of cavities formed at impact of a steady planar jet onto still water were measured on the basis of a high-speed, high-resolution back-light imaging technique. The characteristic time and length scales to define deformation of the cavities, depending on the impact velocity, were analyzed to identify the mechanisms of the cavity growth. The both capillary and vortex-induced pressure are found to govern the local cavity behaviors. - INTERACTION BETWEEN SEA ICE FLOES DRIVEN BY RUN-UP TSUNAMI AND A STRUCTURE WITH PILOTI COLUMN CONSTRUCTION
KIOKA Shinji; ENDO Tsutomu; TAKEUCHI Takahiro; WATANABE Yasunori
PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 71, 2, I_919, I_924, Japan Society of Civil Engineers, 2015
Japanese, We performed model experiments to clarify the increased risks caused by sea ice floes driven by runup tsunami against a structure with piloti column construction, which has been applied to a tsunami evacuation facility. After the collision force imparted by the ice floes acts on the columns, the run-up flow is dammed by the formation of ice jams and ice pile-ups between the columns, and a large static force in the main flow direction. The force is one order of magnitude greater than that in case without ice floes, also acts on the structure because of the water level rise and the ice pile-ups in front of the structure and because of hydrostatic pressure between the columns due to the ice-jam, and this steady state remains for some time. A large force in the vertical direction also acts on the structure, which is the same level as that in the main flow direction. We suggested that, in designing of structures with openings, such as windows and space between columns, the design force for tsunami flow acting on such parts should not be reduced because of the formation of the ice jams and pile-ups. We also suggested that we should evacuate to higher places than usual, because of the water level rise and the ice pile-ups. - Unstable behaviours of cavities formed by steady planar jets on still water
渡部靖憲; 牧田拓也; 小柳津遥陽
土木学会論文集 B2(海岸工学)(Web), 71, 2, 2015 - Kinetic and geometric properties of run-up wave fronts induced by dam-break flows
渡部靖憲; 大島悠揮
土木学会論文集 B2(海岸工学)(Web), 71, 2, 2015 - AN EXPERIMENTAL STUDY OF 3D ANTIDUNE STANDING WAVES
井上卓也; 長谷川和義; 渡部靖憲; 船木淳悟
土木学会論文集 A2(応用力学)(Web), 71, 2, 2015 - ROTATING FLUID EXPERIMENT WITH BOTTOM SUBJECTED TO HEATED AND COOLED
一瀬輪子; 北野慈和; 山田朋人; 渡部靖憲; 泉典洋
土木学会論文集 G(環境)(Web), 71, 5, 2015 - INTERACTION BETWEEN SEA ICE FLOES DRIVEN BY RUN-UP TSUNAMI AND A STRUCTURE WITH PILOTI COLUMN CONSTRUCTION
木岡信治; 遠藤強; 竹内貴弘; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 71, 2, 2015 - Characteristics of sea ice floes run-up caused by tsunami considering ice jams and ice pile-ups around structures0
Shinji Kioka; Takahiro Takeuchi; Yasunori Watanabe
Proceedings of the International Offshore and Polar Engineering Conference, 2015-January, 778, 782, 2015, [Peer-reviewed]
International conference proceedings - Water Exchange at the Mouth of Tanabe Bay in Kii Peninsula, Japan
内山 雄介; 松川 大佑; 神吉 亮佑; 馬場 康之; 森 信人; 水谷 英朗; 渡部 靖憲; 大塚 淳一; 山田 朋人; 猿渡 亜由未; 二宮 順一
土木学会論文集B2(海岸工学) = Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 70, 2, I_446, I_450, Japan Society of Civil Engineers, Nov. 2014
Japanese, Tanabe bay is a small embayment connected directly to the Pacific Ocean to the south, whereas frequently suffers from harmful algal blooms due to sewage effluent and the local aquaculture industry. For preserving the ecosystem in the bay, it is necessary to understand an oceanic structure in the bay along with water exchange at the bay entrance. We thus conduct a comprehensive investigation consisting of a shipboard measurement, a season-long platform observation, and a triply nested high-resolution ocean modeling. The water exchange at the bay mouth is largely affected by semi-diurnal tidal currents and episodic subtidal intrusion of the offshore water controlled by mesoscale circulations. - THE SOURCE AREA OF THE TSUNAMIGENIC TURBIDITY CURRENT IN THE GREAT EAST JAPAN EARTHQUAKE
和田 萌実; 泉 典洋; 渡部 靖憲
水工学論文集 土木学会水工学委員会 編, 58, 70, 1177, 1182, 土木学会, Feb. 2014
Japanese - Run-up waves formed at various relative impact angle to bottom walls
WATANABE Yasunori; OSHIMA Yuki
PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 70, 2, I_186, I_190, Japan Society of Civil Engineers, 2014
Japanese, Imaging measurements of runup dam-break waves over sloping beds were performed for identifying kinematic features of wave propagation and free-surface transition. It has been found that typical blob like front shapes with transverse undulations were developed during propagation especially on highly sloping beds. The rolling motion of the wave front at the bed contact was observed to entrain air beneath the water layer behind the front, which becomes mechanically unstable to be fragmented into bubbles and to affect the wave forms. - Characteristics of Run-up Tsunami with Sea Ice Floes in Urban Area
KIOKA Shinji; MORI Masaya; ENDO Tsutomu; TAKEUCHI Takahiro; WATANABE Yasunori
PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 70, 2, I_821, I_825, Japan Society of Civil Engineers, 2014
Japanese, We made model experiments on run-up tsunami inunduation flow with sea ice floes in an urban area. After the collision force of ice acts on structures, flow is dammed up due to the formation of Ice-jam between the structures, and large static force also acts on the structures because of water level rise and water pressure between the structures due to the jamming. The steady state is kept for a while. While we developed a simple mechanical model for estimation of the water depth and the tsunami force at the steady state, we compared calculated values by this model with experimental ones to verify the validity of the model. Further, in the design of facilities with openings such as windows and pilotis, we proposed that the design force by tsunami current acting on such parts should not be reduced because of the jamming. - Oxygen Transfer model for Bubble-Laden Turbulence Generated by Plunging Liquid Jets
NIIDA Yasuo; WATANABE Yasunori
PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 70, 2, I_51, I_55, Japan Society of Civil Engineers, 2014
Japanese, This paper proposed an oxygen transfer model for bubble-laden turbulence generated by plunging jets. The proposing model has been validated through comparisons with experiments for bubble velocity, liquid velocity, liquid turbulence and oxygen flux. It was found dissolved oxygen concentrations in bubbly flows was determined by local bubble behaviors and turbulent flows modified around bubbles. This bubble-mediated gas transfer via mechanical interaction between bubbles and turbulence is important to understand air-sea gas exchange in the surf zone. - Bubble-turbulence interactions model in a stochastic-LES framework
WATANABE Yasunori; OYAIZU Haruhi; NIIDA Yasuo
PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 70, 2, I_61, I_65, Japan Society of Civil Engineers, 2014, [Peer-reviewed]
Japanese, Scientific journal, This paper presents a novel stochastic-LES hybrid model for favre averaged bubble-turbulence interactions in free-surface flows. The current model is found to be capable of computing local behaviors of dense bubble flows coupled with fluid turbulent motion, which is ensured by comparisons with experimental observations. The model is also applied to the flow at a planar jet impact onto a still water, as a model of overturning jets of breaking waves, which reasonably computed cavity deformation, air tube entrainment and bubble formations. - Water Exchange at the Mouth of Tanabe Bay in Kii Peninsula, Japan
内山雄介; 松川大佑; 神吉亮佑; 馬場康之; 森信人; 水谷英朗; 渡部靖憲; 大塚淳一; 山田朋人; 猿渡亜由未; 二宮順一
土木学会論文集 B2(海岸工学)(Web), 70, 2, 2014 - Bubble-turbulence interactions model in a stochastic-LES framework
渡部靖憲; 小柳津遥陽; 新井田靖郎
土木学会論文集 B2(海岸工学)(Web), 70, 2, 2014 - Oxygen Transfer model for Bubble-Laden Turbulence Generated by Plunging Liquid Jets
新井田靖郎; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 70, 2, 2014 - Run-up waves formed at various relative impact angle to bottom walls
渡部靖憲; 大島悠揮
土木学会論文集 B2(海岸工学)(Web), 70, 2, 2014 - Water Temperature Variation at the Mouth of Tanabe Bay during Typhoon Passing
馬場康之; 水谷英朗; 久保輝広; 内山雄介; 森信人; 渡部靖憲; 大塚淳一; 山田朋人; 猿渡亜由未; 二宮順一
土木学会論文集 B2(海岸工学)(Web), 70, 2, 2014 - THE SOURCE AREA OF THE TSUNAMIGENIC TURBIDITY CURRENT IN THE GREAT EAST JAPAN EARTHQUAKE
和田萌実; 泉典洋; 渡部靖憲
土木学会論文集 B1(水工学)(Web), 70, 4, 2014 - Characteristics of Run-up Tsunami with Sea Ice Floes in Urban Area
木岡信治; 森昌也; 遠藤強; 竹内貴弘; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 70, 2, 2014 - CURRENT INDUCED BY BREAKING OF INTERNAL KELVIN WAVES ON SLOPES WITH DIFFERENT ANGLES
小窪一毅; 中山恵介; 新谷哲也; 大塚淳一; 渡部靖憲; 柿沼太郎; 駒井克昭; 清水健司
土木学会論文集 B3(海洋開発)(Web), 70, 2, I.193-I.198 (J-STAGE), 2014, [Peer-reviewed]
Japanese, Scientific journal - DEVELOPMENT AND DAMPING OF HORIZONTAL CIRCULATION INDUCED BY BREAKING OF INTERNAL KELVIN WAVES
小窪一毅; 中山恵介; 新谷哲也; 大塚淳一; 渡部靖憲; 柿沼太郎; 駒井克昭; 清水健司
土木学会論文集 B1(水工学)(Web), 70, 4, I.1195-I.1200 (J-STAGE), I_1200, Japan Society of Civil Engineers, 2014, [Peer-reviewed]
Japanese, Scientific journal, This study describes a horizontal circulation induced by the breaking of internal Kelvin waves over a uniform slope. In lakes or coastal regions, wind stress over a water surface or tide at the bay mouth may induce internal waves, which deform as internal Kelvin waves when the inertia radius is equal or less than the spatial scale of a lake or a bay. In general, internal Kelvin waves break due to the topographical features, such as a slope, which is revealed to cause horizontal circulation in the upper layer. The previous studies demonstrated that a horizontal circulation is induced due to the secondary lateral current due to the breaking of internal Kelvin waves over a slope. However, the development and damping of the horizontal circulation have not been clarified. Therefore, this study aims to investigate the occurrence of a horizontal circulation due to the internal Kelvin wave breaking over a slope by using laboratory experiments and numerical computations. - Nationwide post event survey and analysis of the 2011 Tohoku earthquake tsunami
Nobuhito Mori; Tomoyuki Takahashi; Shun Etsu Hamaura; Kazuya Miyakawa; Katsuhiko Tanabe; Keisuke Tanaka; Mitsuyuki Tanaka; Tsukasa Watanabe; Hideo Matsutomi; Kazunori Naoe; Takuya Noumi; Erika Yamaguchi; Shoichi Ando; Yushiro Fujii; Toshihide Kashima; Yasuo Okuda; Bun'ichiro Shibazaki; Tsutomu Sakakiyama; Masafumi Matsuyama; Takumi Yoshii; Kazuhisa Goto; Takashi Aida; Yuuji Kurata; Mabumi Miyazaki; Katuya Shutou; Jun Suzuki; Hikari Takeuchi; Takayuki Nakamura; Osamu Fujiwara; Kyoko Kagohara; Haruo Kimura; Junko Komatsubara; Yukari Miyashita; Yuichi Namegaya; Yuki Sawai; Masanobu Shishikura; Koichiro Tanigawa; Hermann Fritz; Ken Ichi Uzaki; Mikio Sasaki; Masato Minami; Hitoshi Endou; Masaki Hashimoto; Yutaka Kobashigawa; Masamitsu Kumagai; Masahiro Ietsune; Kazuhiko Nakamura; Aditya Gusman; Kazuomi Hirakawa; Kei Loki; Yugo Nakamura; Takafumi Nakayama; Yuichi Nishimura; Puma Putra; Ayumi Saruwatari; Yasunori Watanabe; Tomohito Yamada; Yasunori Nabetani; Hisamichi Nobuoka; Takashi Tamada; Yuriko Matsubayashi; Toshinori Ogasawara; Shigeki Sakai; Masao Abe; Yutaka Hayashi; Hideki Iino; Kazuhiro Iwakiri; Kazuhiro Kimura; Kenji Maeda; Masami Okada; Hiroaki Tsushima; Taro Kakinuma; Kei Yamashita; Shinya Umeda; Takahiro Nakamura; Shuji Seto; Kurokawa Takahiro; Tetsuya Torayashiki; Gozo Tsujimoto; Kohji Uno; Shoichi Yoshioka; Norio Dewa; Tetsuya Hayashi; Mitsuyoshi Kitamura; Shusaku Kuroda; Akihiko Nakahira; Takeshi Nozawa; Kazuya Taniwaki; Kunio Ohtoshi; Takashi Aoyama; Tatsuo Chiba; Hiroshi Enomoto; Kazunori Hirahara; Shigeki Murai; Hiroshi Narayama; Satoshi Yamanaka; Hitoshi Yamazaki; Satoshi Yoshiiri; Ryoukei Azuma; Yasuyuki Baba
Coastal Engineering Journal, 54, 1, 01 Jan. 2014, [Peer-reviewed]
Scientific journal - Modulations of the heat transfer across wind wave surfaces
WATANABE YASUNORI; TASHIRO KOKI; OTSUKA JUN'ICHI; OYAMA TAKAHIRO; YAMADA TOMOHITO
土木学会論文集 B2(海岸工学)(Web), 70, 2, I.56-I.60 (J-STAGE), I_60, Japan Society of Civil Engineers, 2014
Japanese, High speed infrared imaging measurements were performed for identifying mechanical factors to govern surface skin temperatures on wind waves under moderate to strong winds. Surface renewals owing to turbulent disturbances are found to predominantly determine the skin temperature amplitude and phase lags to surface elevation, which is parameterized by a so-called wind-wave Reynolds number (RB). The modulations of the skin temperature variations are observed at RB ~ 4 × 104, indicating governing dynamics to produce surface turbulence is altered at the boundary. - Dynamic Interactions of Free-Surface and Vorticity at Water Impacts on Still Water
Y. Watanabe; A. Saruwatari; D. M. Ingram
Proc. ICNMMF, 2014
English, International conference proceedings - Measurement of Dissolved Carbon Dioxide Concentration in a Surf Zone
J. Otsuka; Y. Watanabe; A. Saruwatari
Proc. Int. Conf. Coastal Eng., 34, 2014
English, International conference proceedings - Simultaneous Image Measurement of Sprays and Air Bubbles Formed during Wind Wave Breaking Event
大塚淳一; 渡部靖憲; 田代晃基; 大山高弘; 猿渡亜由未; 山田朋人
土木学会論文集 B2(海岸工学)(Web), 70, 2, 41, 45, 2014, [Peer-reviewed] - Water Temperature Variation at the Mouth of Tanabe Bay during Typhoon Passing
馬場 康之; 水谷 英朗; 久保 輝広; 内山 雄介; 森 信人; 渡部 靖憲; 大塚 淳一; 山田 朋人; 猿渡 亜由未; 二宮 順一
土木学会論文集B2(海岸工学), 70, 2, I_476, I_480, 土木学会, 2014, [Peer-reviewed]
Japanese - Splash, vortices and turbulent shears in partial dam-break flows - Splash model of wave-breaking and overtopping
Yasunori Watanabe; Shunichi Sato; Yasuo Niida; Ichiro Kimura; Hiroshi Yokota; Haruhi Oyaizu; Yuki Oshima; Ayumi Saruwatari
Proceedings of the Coastal Engineering Conference, 2014-January, 2014, [Peer-reviewed]
International conference proceedings - Laboratory measurement of sediment transport under a breaking wave turbulent flow field
Junichi Otsuka; Yasunori Watanabe
Proceedings of the Coastal Engineering Conference, 2014-January, 2014, [Peer-reviewed]
International conference proceedings - Turbulence Model
Nobuhito Mori; Yasunori Watanabe; Takayuki Suzuki; Akio Okayasu
Computational Wave Dynamics, 15, 44, 01 Jan. 2013
In book - Fundamental Computational Methods
Yasunori Watanabe; Nobuhito Mori
Computational Wave Dynamics, 45, 73, 01 Jan. 2013
In book - Computational Wave Dynamics for Coastal and Ocean Research
Yasunori Watanabe; Nobuhito Mori; Hitoshi Gotoh; Akio Okayasu
Computational Wave Dynamics, 213, 226, 01 Jan. 2013
In book - A STUDY OF TSUNAMI INUNDATION FLOW WITH ICE FLOES IN URBAN AREA
木岡信治; 森昌也; 遠藤強; 竹内貴弘; 渡部靖憲
土木学会論文集 B3(海洋開発)(Web), 69, 2, 2013 - Mechanisms of Horizontal Circulation Induced by Breaking of Internal Kelvin Waves
小窪一毅; 中山恵介; 新谷哲也; 柿沼太郎; 大塚淳一; 渡部靖憲; 駒井克昭; SHIMIZU Kenji
土木学会論文集 B2(海岸工学)(Web), 69, 2, 2013 - Bubble-Mediated Oxygen Transfer from Bubbles Entrained by Jets
新井田靖郎; 渡部靖憲
土木学会論文集 B2(海岸工学)(Web), 69, 2, 2013 - Vorticity Instabilitties in Wave-Breaking Process: Formations of 3D Vortex Structure, Finger Jets and Sea Sprays
渡部靖憲; 泉典洋; 猿渡亜由未
土木学会論文集 B2(海岸工学)(Web), 69, 2, 2013 - Mechanical Balance to Form Flow Structures in a Run-Up Wave
渡部靖憲; 堀井正輝; 新井田靖郎
土木学会論文集 B2(海岸工学)(Web), 69, 2, 2013 - Dynamic Fluid responses under Overfow due to Partial Collapse of Water Column
渡部靖憲; 佐藤駿一; 三戸部佑太; 横田弘
土木学会論文集 B2(海岸工学)(Web), 69, 2, 2013 - Mechanisms of Horizontal Circulation Induced by Breaking of Internal Kelvin Waves
KOKUBO Kazuki; NAKAYAMA Keisuke; SHINTANI Tetsuya; KAKINUMA Taro; OTSUKA Jyunichi; WATANABE Yasunori; KOMAI Katsuaki; SHIMIZU Kenji
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 69, 2, I_451, I_455, 公益社団法人 土木学会, 2013, [Peer-reviewed]
Japanese, Scientific journal, In enclosed bays, a two-layer system is likely to be formed due to the fresh water from rivers and solar radiation in summer. External forces, such as wind and tide, cause internal waves in a two-layers system, in which the Coriolis effect induces internal Kelvin waves. When internal Kelvin waves propagate over a slope, they break and cause turbulence, which results in the occurrence of horizontal circulation. However, previous studies have not revealed how breaking induces horizontal circulation. Therefore, this study aims to clarify the mechanisms of horizontal circulation induced by the breaking of internal Kelvin waves by using numerical analysis and laboratory experiments. - EVACUATION BEHAVIORS OF COASTAL RESIDENTS IN HOKKAIDO FOR THE 2011 TOHOKU EARTHQUAKE TSUNAMI
田中岳; 渡部靖憲; 中津川誠
土木学会論文集 B2(海岸工学)(Web), 69, 1, 48-63 (J-STAGE), 2013, [Peer-reviewed]
Japanese, Scientific journal - Bubble-Mediated Oxygen Transfer from Bubbles Entrained by Jets
新井田 靖郎; 渡部 靖憲
土木学会論文集. B2, 海岸工学, 69, 2, 46, 50, 土木学会, 2013
Japanese - Dynamic Fluid responses under Overflow due to Partial Collapse of Water Column
渡部 靖憲; 佐藤 駿一; 三戸部 佑太
土木学会論文集. B2, 海岸工学, 69, 2, 176, 180, 土木学会, 2013, [Peer-reviewed]
Japanese - Mechanical Balance to Form Flow Structures in a Run-Up Wave
渡部 靖憲; 堀井 正輝; 新井田 靖郎
土木学会論文集. B2, 海岸工学, 69, 2, 66, 70, 土木学会, 2013, [Peer-reviewed]
Japanese, Scientific journal - Vorticity Instabilities in Wave-Breaking Process : Formations of 3D Vortex Structure, Finger Jets and Sea Sprays
渡部 靖憲; 泉 典洋; 猿渡 亜由未
土木学会論文集. B2, 海岸工学, 69, 2, 51, 55, 土木学会, 2013, [Peer-reviewed]
Japanese - IMAGING TECHNIQUE TO MEASURE DEFORMATIONS OF WAVE-DISSIPATING STRUCTURES
Yuta Mitobe; Yasunori Watanabe
COASTAL STRUCTURES 2011, VOL 1 & 2, 767, 774, 2013, [Peer-reviewed]
English, International conference proceedings - Current induced by breaking of internal Kelvin waves
K. Nakayama; K. Kokubo; T. Shintani; J. Otsuka; Y. Maruya; Y. Watanabe; K. Komai; T. Okada
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 68, 2, 926, 930, Japan Society of Civil Engineers, Nov. 2012, [Peer-reviewed]
Japanese, Scientific journal - Evolution of the 2011 Tohoku earthquake tsunami on the pacific coast of Hokkaido
Yasunori Watanabe; Yuta Mitobe; Ayumi Saruwatari; Tomohito Yamada; Yasuo Niida
Coastal Engineering Journal, 54, 1, Mar. 2012, [Peer-reviewed]
Scientific journal - Evolution of the 2011 Tohoku Earthquake Tsunami on the Pacific Coast of Hokkaido
Watanabe Yasunori; Mitobe Yuta; Saruwatari Ayumi; Yamada Tomohito; Niida Yasuo
Coastal Engineering Journal, 54, 1, 1250002, 1250002, Mar. 2012, [Peer-reviewed]
English, Scientific journal - Experimental Study of the Turbulent Flow Field and Sediment Transport under Breaking Waves
大塚淳一; 渡部靖憲; 林倫史
土木学会論文集 B2(海岸工学)(Web), 68, 2, 2012 - An imaging measurement for advection-diffusion velocity of heat and materials
渡部靖憲; 佐藤駿一
土木学会論文集 B2(海岸工学)(Web), 68, 2, 2012 - Transitional velocity and shear distributions in a runup wave
渡部靖憲; 堀井正輝
土木学会論文集 B2(海岸工学)(Web), 68, 2, 2012 - A study of elastic properties of URu2Si2 in comparison with the non-5f contribution of ThRu2Si2
T. Yanagisawa; H. Saito; Y. Watanabe; Y. Shimizu; H. Hidaka; H. Amitsuka
Journal of Physics: Conference Series, 391, 1, Institute of Physics Publishing, 2012, [Peer-reviewed]
English, International conference proceedings - Recovery of nori Porphyra color by uptake of nutrients supplied intermittently from rivers
Shuzo Takagi; Yasuko Shimizu; Koji Kusaka; Tokishige Fujisawa; Munehiro Fujiwara; Yasunori Watanabe; Tateki Fujiwara
Nippon Suisan Gakkaishi (Japanese Edition), 78, 2, 246, 255, 2012, [Peer-reviewed]
Japanese, Scientific journal - Transitional velocity and shear distributions in a runup wave
渡部 靖憲; 堀井 正輝
土木学会論文集. B2, 海岸工学, 68, 2, 56, 60, 土木学会, 2012
Japanese - Experimental Study of the Turbulent Flow Field and Sediment Transport under Breaking Waves
大塚 淳一; 渡部 靖憲; 林 倫史
土木学会論文集. B2, 海岸工学, 68, 2, 481, 485, 土木学会, 2012, [Peer-reviewed]
Japanese - Length and Velocity Scales of Breaking Waves
三戸部 佑太; 渡部 靖憲
土木学会論文集. B2, 海岸工学, 68, 2, 31, 35, 土木学会, 2012, [Peer-reviewed]
Japanese - An imaging measurement for advection-diffusion velocity of heat and materials
渡部 靖憲; 佐藤 駿一
土木学会論文集. B2, 海岸工学, 68, 2, 41, 45, 土木学会, 2012, [Peer-reviewed]
Japanese - Wave flume-based evaluation of suspended sand transport in breaking waves
Junichi Otsuka; Yasunori Watanabe
Proceedings of the Coastal Engineering Conference, 2012, [Peer-reviewed]
International conference proceedings - Bioluminescence imaging for measuring fluid shear distrubutions
Yasunori Watanabe; Jun Sakai; Yuta Mitobe; Yasuo Niida
Proceedings of the Coastal Engineering Conference, 2012, [Peer-reviewed]
International conference proceedings - AN IMAGING TECHNIQUE FOR MEASURING WAVE SURFACE SHAPES
Yasunori Watanabe; Yuta Mitobe; Kaori Oshima
COASTAL ENGINEERING JOURNAL, 53, 4, 549, 565, Dec. 2011, [Peer-reviewed]
English, Scientific journal - Application of adaptive mesh refinement to tsunami computation
Yasunori Watanabe; Yuta Mitobe; Yasuo Niida; Tomohito Yamada
Proceedings of the International Offshore and Polar Engineering Conference, 218, 223, 19 Sep. 2011
International conference proceedings - Bioluminescence-based imaging technique for pressure measurement in water
Yasunori Watanabe; Yasufumi Tanaka
EXPERIMENTS IN FLUIDS, 51, 1, 225, 236, Jul. 2011, [Peer-reviewed]
English, Scientific journal - Measurement of Oxygen Transfer from Air Bubbles to Water
新井田 靖郎; 渡部 靖憲
土木学会論文集. B2, 海岸工学, 67, 2, 66, 70, 土木学会, 2011, [Peer-reviewed]
Japanese - A Three-Dimensional Visualization of Moving Air Bubbles Bubbly Flows
森 信人; 加島 寛章; 渡部 靖憲
可視化情報学会誌, 31, 1, 63, 68, 可視化情報学会, 2011, [Peer-reviewed]
Japanese - Quantitative Description of Local Breaking-Wave Shapes
三戸部 佑太; 渡部 靖憲
土木学会論文集. B2, 海岸工学, 67, 2, 86, 90, 土木学会, 2011, [Peer-reviewed]
Japanese - Wave Flume Measurements of Suspended Sediment Velocity and Flux in a Surf Zone
大塚 淳一; 渡部 靖憲
土木学会論文集. B2, 海岸工学, 67, 2, 91, 95, 土木学会, 2011, [Peer-reviewed]
Japanese - Computational Scheme to Fulfill Dynamic Boundary Conditions at Gas-Liquid Interface
渡部 靖憲; 岩下 厚志
土木学会論文集. B2, 海岸工学, 67, 2, 16, 20, 土木学会, 2011, [Peer-reviewed]
Japanese - Interfacial Process of Ocean under Rainfall
渡部 靖憲; 但木 慎治; 山田 朋人
土木学会論文集. B2, 海岸工学, 67, 2, 61, 65, 土木学会, 2011, [Peer-reviewed]
Japanese - Geometric features of tidal channel networks
岩崎 理樹; 渡部 靖憲; 奥寺 亮太
土木学会論文集. B2, 海岸工学, 67, 2, 951, 955, 土木学会, 2011, [Peer-reviewed]
Japanese - Turbulent behavior of fluidized sediments in composite shear flow
Ayumi Saruwatari; Wataru Matsuzaki; Yasunori Watanabe
Proceedings of the Coastal Engineering Conference, 01 Dec. 2010
International conference proceedings - Measurement of dissolved carbon dioxide concentration in a surf zone
Junichi Otsuka; Yasunori Watanabe; Ayumi Saruwatari
Proceedings of the Coastal Engineering Conference, 01 Dec. 2010
International conference proceedings - Application of les-stochastic two-way model to two-phase boundary layer flows
Yasunori Watanabe; Yuta Mitobe; Yasuo Niida; Ayumi Saruwatari
Proceedings of the Coastal Engineering Conference, 01 Dec. 2010
International conference proceedings - LES-stochastic coupling model of bubble-laden turbulence
Y. Niida; Y. Mitobe; Y. Watanabe
Proceedings of the International Offshore and Polar Engineering Conference, 3, 750, 754, 10 Sep. 2010
International conference proceedings - Image measurements of three-dimensional shapes of solid objects and liquid free surfaces
Y. Mitobe; Y. Niida; Y. Watanabe
Proceedings of the International Offshore and Polar Engineering Conference, 3, 745, 749, 10 Sep. 2010
International conference proceedings - High-resolution, high-speed computations of tsunami waves using adaptive mesh refinement
Watanabe Yasunori
Proceedings, ... meeting of Japan Society of Fluid Mechanics, 2010, 0, 293, 293, 日本流体力学会, 2010, [Peer-reviewed]
Japanese, Adaptive mesh refinement (AMR) is one of the powerful computational tools to enhance local computing resolution at less costs. In this paper, computational performances of AMR for tsunami simulations were examined through computational tests for long wave propagation initiated by collapse of the water column on still water in terms of the accuracy and computational cost. AMR was also applied to a practical tsunami evolution-2003 Tokachioki earthquake tsunami, which was compared with measured water elevation for examining the certainties of this method. It was found through the numerical tests that the present method is capable of efficiently performing reliable computations of tsunami propagation at high resolution. - Image measurement of free-surface shapes and its application to breaking waves
三戸部 佑太; 大島 香織; 渡部 靖憲
J. JSCE. Ser. B2, Coastal engineering, 66, 1, 86, 90, 土木学会, 2010
Japanese - Lateral instability of overtopping jets evolving into fingering surfaces
渡部 靖憲; 石崎 真一郎; 新井田 靖郎
J. JSCE. Ser. B2, Coastal engineering, 66, 1, 76, 80, 土木学会, 2010
Japanese - Bioluminescence imaging measurements of oscillatory shear flows
渡部 靖憲; 坂井 純
J. JSCE. Ser. B2, Coastal engineering, 66, 1, 71, 75, 土木学会, 2010
Japanese - Scarifying and fingering surfaces of plunging jets
Ayumi Saruwatari; Yasunori Watanabe; David M. Ingram
COASTAL ENGINEERING, 56, 11-12, 1109, 1122, Nov. 2009, [Peer-reviewed]
English, Scientific journal - Bioluminescence imaging measurements of impact fluid pressure
渡部 靖憲; 田中 康文; 坂井 純
Journal of coastal engineering, JSCE, 56, 0, 831, 835, 土木学会, Oct. 2009
Japanese - Image measurements of three-dimensional shapes of solid objects and liquid free-surfaces
渡部 靖憲; 三戸部 佑太
Journal of coastal engineering, JSCE, 56, 0, 1466, 1470, 土木学会, Oct. 2009, [Peer-reviewed]
Japanese - Mechanisms of the local surface deformation and breakup of the wave breaking jets
猿渡 亜由未; 渡部 靖憲
Journal of coastal engineering, JSCE, 56, 0, 16, 20, 土木学会, Oct. 2009, [Peer-reviewed]
Japanese - Characteristics of spanwise velocity distributions and vortex scales in breaking waves
大塚 淳一; 渡部 靖憲
Journal of coastal engineering, JSCE, 56, 0, 91, 95, 土木学会, Oct. 2009, [Peer-reviewed]
Japanese, Scientific journal - Fingering and fragmenting processes of overtopping flip-through jets
渡部 靖憲; 石崎 真一郎
Journal of coastal engineering, JSCE, 56, 0, 11, 15, 土木学会, Oct. 2009, [Peer-reviewed]
Japanese - Stochastic models of entrainment and advection of air bubbles under jets
渡部 靖憲; 新井田 靖郎; 猿渡 亜由未
Journal of coastal engineering, JSCE, 56, 0, 6, 10, 土木学会, Oct. 2009, [Peer-reviewed]
Japanese - DYNAMIC EFFECTS OF SUSPENDED SEDIMENTS ON TURBULENT FLOWS OVER DUNES
CHICHIBU Kohtaro; WATANABE Yasunori; SHIMIZU Yasuyuki
Journal of hydroscience and hydraulic engineering, 27, 1, 1, 10, 01 May 2009, [Peer-reviewed]
English - Stochastic Models of Entranment and Advection of Air Bubbles under Jets
WATANABE Yasunori; NIIDA Yasuo; SARUWATARI Ayumi; SAEKI Hiroshi
PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 65, 1, 6, 10, Japan Society of Civil Engineers, 2009
English, Two-way stochastic subgrid bubble models to determine the number density and sizes of small air-bubbles entrained under circular jets and the advetion and diffusion process for Large Eddy Simulation (LES) are proposed in this paper. The proposing model has been applied to two simple air-water two phase flows - the bubble flow in still water as well as the aerated flow under circular jet flowing into still water. It was found that the bubble motion intensifies the turbulence, which enhances fluctuating bubble motion. This air-water energy tranfer via turbulent interaction is important factor to determine the near-surface fluid dynamics. - Fingering and fragmenting precesses of overtopping flip-through jets
WATANABE Yasunori; ISHIZAKI Shin-ichiro
PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 65, 1, 11, 15, Japan Society of Civil Engineers, 2009
English, A flip-through overtopping jet evolves into laterally deintegrated jets, so-called finger jets, at an early stage of the wave uprush on a vertical wall. The finger jets are vertically stretched to fragment into small multiple droplets or sprays. In this study, these fingering and fragmenting processes were visualized, and the shapes of the jets and sprays were quantitatively measured on the basis of novel level-set image detecting algorithm. The evolution of the size distributions and water volume fractions for the both jets and sprays were characterized via spectrum image analysis. - 砕波フィンガージェットと飛沫の生成機構
猿渡亜由未; 渡部靖憲
混相流学会年会講演会論文集, 96, 97, 2009, [Peer-reviewed]
Japanese, Scientific journal - Transport of Carbon Dioxide Under Breaking Waves
Ayumi Saruwatari; Kota Watanabe; Yasunori Watanabe
海洋開発論文集, 25, 837, 841, 2009, [Peer-reviewed]
Japanese, Scientific journal - LASER INDUCED FLUORESCENCE MEASUREMENTS OF CARBON DIOXIDE DISSOLUTION IN WAVE-BREAKING TURBULENCE
Yasunori Watanabe; Junichi Otsuka; Ayumi Saruwatari
COASTAL ENGINEERING 2008, VOLS 1-5, 51, +, 2009, [Peer-reviewed]
English, International conference proceedings - SPRAYS AND FINGER JETS EVOLUTION FROM SPLASHING JETS
Ayumi Samwatari; Yasunori Watanabe
PROCEEDINGS OF COASTAL DYNAMICS 2009, 2009, [Peer-reviewed]
English, International conference proceedings - TRANSITION FROM SPLASHING JETS TO FRAGMENTED FINGERS AND SPRAYS
Ayumi Saruwatari; Yasunori Watanabe
COASTAL ENGINEERING 2008, VOLS 1-5, 73, +, 2009, [Peer-reviewed]
English, International conference proceedings - SPRAY SIZE DISTRIBUTIONS AT FLIP-THROUGH WAVE OVERTOPPING
Yasunori Watanabe; Shin-ichiro Ishizaki
PROCEEDINGS OF COASTAL DYNAMICS 2009, 2009, [Peer-reviewed]
English, International conference proceedings - Fundamental study for measuring spatial distributions of impact pressure by bioluminescence
渡部 靖憲; 田中 康文
Journal of coastal engineering, JSCE, 55, 0, 846, 850, 土木学会, Oct. 2008, [Peer-reviewed]
Japanese - Physical mechanisms for forming finger jets and sprays
猿渡 亜由未; 渡部 靖憲
Journal of coastal engineering, JSCE, 55, 0, 61, 65, 土木学会, Oct. 2008, [Peer-reviewed]
Japanese - Size spectra of sprays at flip-through overtopping
渡部 靖憲; 石崎 真一郎
Journal of coastal engineering, JSCE, 55, 0, 76, 80, 土木学会, Oct. 2008, [Peer-reviewed]
Japanese, Scientific journal - Visualization of Bubble and Sea Spray at Air-Water Interface : Microscopic Characteristics of Sea Surface Wave Breaking
MORI Nobuhito; WATANABE Yasunori
Journal of Japan Society of Fluid Mechanics, 27, 4, 311, 320, Japan Society of Fluid Mechanics, 25 Aug. 2008, [Peer-reviewed]
Japanese, A wave breaking in the surf zone generates sea bubbles into the sea and releases air spray into the atmosphere. The sizes of air bubbles and spray are widely distributed from micrometer to centimeter. Moreover, these bubbles and spray are generated inhomogeneously both temporally and spatially. The two-phase flow measurements using imaging technique for two-dimensional bubble measurements are summarized for the surf zone breaking waves. The characteristics of air bubbles and sprays in the surf zone such as number distributions, bubble size spectra, and turbulent characteristics of fluid velocity are reviewed based on the visualization technique developed recently. - Infrared measurements of surface renewal and subsurface vortices in nearshore breaking waves
WATANABE Yasunori; MORI Nobuhito
J Geophys Res, 113, C7, C07015-C07015-21, 22 Jul. 2008, [Peer-reviewed]
English - Infrared measurements of surface renewal and subsurface vortices in nearshore breaking waves
Yasunori Watanabe; Nobuhito Mori
Journal of Geophysical Research: Oceans, 113, 7, Blackwell Publishing Ltd, 08 Jul. 2008, [Peer-reviewed]
English, Scientific journal - Infrared measurements of surface renewal and subsurface vortices in nearshore breaking waves
Yasunori Watanabe; Nobuhito Mori
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 113, C7, Jul. 2008, [Peer-reviewed]
English, Scientific journal - Free-surface flows under impacting droplets
Watanabe Yasunori; Saruwatari Ayunii; Ingram David M.
Journal of Computational Physics, 227, 4, 2344, 2365, 01 Feb. 2008, [Peer-reviewed]
English, Scientific journal - New imaging technique for measuring fluid and solid velocities in sand-laden flows over dunes in an open channel
K. Chichibu; Y. Watanabe; Y. Shimizu
RIVER, COASTAL AND ESTUARINE MORPHODYNAMICS: RCEM 2007, VOLS 1 AND 2, 1, 627, 632, 2008
English, International conference proceedings - Irrotational, rotational and turbulent flows in breaking waves
Yasunori Watanabe; Ayumi Saruwatari
Proceedings of the Coastal Engineering Conference, 62, 72, 01 Dec. 2007
International conference proceedings - EXPERIMENTAL STUDY OF MECHANISM TO PRODUCE IMPACT WAVE PRESSURES
OTSUKA Junichi; TANAKA Yasufumi; WATANABE Yasunori
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 23, 23, 195, 200, Japan Society of Civil Engineers, 2007
Japanese, In this study, the mechanism to produce impact pressure on a wall under fresh water and sea water jets is experimentally investigated through water drop tests. The effects of entrapped air, which is a model of an air pocket formed at coastal structure under breaking waves, are also discussed. Higher impact pressure is found to occur under sea water jets rather than fresh water jet for all cases. It is also found that the entrapped air has a role to reduce the pressure maximal and to change peak frequencies of the impacts. New model to estimate variations of the impact pressure with coefficients determined through the experiments is proposed. It is roughly applicable to estimate the maximum pressure and the duration of the impacts under the jets. - A Three-Dimensional Visualization of Air Bubbles in Bubbely Flows
KASHIMA Hiroaki; MORI Nobuhito; WATANABE Yasunori; OTSUKA Junichi
PROCEEDINGS OF COASTAL ENGINEERING, JSCE, 54, 54, 1466, 1470, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
A three-dimensional visualization method (3D-BTV) for bubble measurements was developed to measure bubble shapes and velocities in a liquid. The 3D-BTV method is based on the combination the 3D shadow graph method and 3D super resolution particle tracking velocimetry. The proposed method was verified by virtual experiments and the real measurements of air bubble motions in the water, respectively. In this study, it can be realized that The 3D-BTV method has capability to measure the both bubble shapes and motions in the 3D space with highly temporal-spatial resolution in comparison with the previous technique. - LES-Stochastic Two-Way Model and its Application to Two-Phase Flows in a Wave Boundary Layer
WATANABE Yasunori; MIYAKI Yasuhiro; SARUWATARI Ayumi; TANAKA Yasufumi; OTSUKA Junichi; SAEKI Hiroshi
PROCEEDINGS OF COASTAL ENGINEERING, JSCE, 54, 54, 36, 40, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
Japanese, Scientific journal, This paper presents a suspended-particle/liquid two-way coupling model integrated with conventional stochastic and subgrid stress models of a large eddy simulation. The model is applied to particle laden turbulent flows in a wave boundary layer developed over a flat sea bed for understanding dynamic effects of turbulence on the particle size, number density and the density. The turbulence intensification due to the presence of particles results in additional suspensions from the bed, featuring a recursive turbulence/suspension interaction process of the particle laden flow within the boundary layer. - Dynamics of the local free-surface and sub-surface vortex under splashing jet
Ayumi Saruwatari; Yasunori Watanabe
Proc. Int. Conf. Violent Flows (VF-2007), 315, 318, 2007, [Peer-reviewed]
English, International conference proceedings - Measurement of dissolved CO2 in water under breaking waves
OTSUKA Junichi; HIBATA Hazumi; WATANABE Yasunori
PROCEEDINGS OF COASTAL ENGINEERING, JSCE, 54, 54, 51, 55, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
In this study, distributions of dissolved CO2 under breaking waves are experimentally measured using two-color Laser Induced Fluorescence (LIF). CO2 mainly dissolves on gas/water interfaces of the plunging waves and around bubbles entrained by successive plunging jets. vortices induced by the jets quickly diffuse downward the dissolved CO2 together with the bubbles. Undertow transport the dissolved CO2 offshoreward below the trough level for enhancing the CO2 concentration in a whole surf zone. - Fragmentation Model for Jetting Free-Surface Flows
SARUWATARI Ayumi; WATANABE Yasunori
PROCEEDINGS OF COASTAL ENGINEERING, JSCE, 54, 54, 66, 70, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
In this paper, a fragmentation model of jets with free-surfaces, describing evolution of the size spectra of sprays during the fragmentation process is developed. A 3-D large eddy simulation reproduces amplification of free-surface disturbances of the jets induced by the counter-rotating vortices and the resulting jetting flows splitting into fingers and sprays. It is found that a probability density of the finger or spray size can be described by a log-normal distribution, and its evolution depends on Weber number. The present fragmentation model is capable of predicting the volume fraction of the jets at arbitrary time after the inception of fragmentation. - Dissipation Performance of the Long-Period Wave Absorbing Structure with Oblique Walls
OHSHIMA Kaori; MORIYA Yoichi; OTSUKA Junichi; WATANABE Yasunori
PROCEEDINGS OF COASTAL ENGINEERING, JSCE, 54, 54, 796, 800, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
Long-period waves are often trapped in a port and harbor, and cause disturbances of cargo handling and damages of mooring ropes for ships. A new type of long-period wave absorption structure which involves two oblique walls and a vertical slit between them has been developed for dissipate the waves. In this paper, through a large eddy computer simulation and visual experimental measurement, flow patterns and vortex structures formed with the proposing structure, depending on a relative structure length with incident wavelength, are investigated. The long-period waves are found to be reduced via a combination of energy exchanges to a pair of circulated flows trapped with in the structure and of energy dissipation due to turbulent jets formed at the slit. - Measurement of Entrained Air Bubbles and Vortices in Breaking Waves
Otsuka Junichi; Watanabe Yasunori
Proceedings, ... meeting of Japan Society of Fluid Mechanics, 2007, 0, 47, 47, 日本流体力学会, 2007, [Peer-reviewed]
Japanese, Breaking waves produce numbers of vortices through a jet splashing process and also entrain many air bubbles, forming complicated air-water two-phase turbulent flow field in a surf zone. In this research, a simultaneous velocity measurement technique of water and bubble flows in breaking waves is developed for characterizing water-bubble interactions within vortices in a surf zone. The bubbles and neutral buoyant tracers are separately recorded by two different digital video cameras on the basis of an optical filtering technique. It is found that bubble motion does not follow water flow in a vortex, and mean bubble velocity is always higher than water velocity in breaking waves. Bubble-induced turbulent energy is estimated to be less than 10% of total turbulent energy. - Application of three-dimensional hybrid stereoscopic particle image velocimetry to breaking waves
Yasunori Watanabe; Yoshiyasu Hideshima; Takaaki Shigematsu; Kohsei Takehara
MEASUREMENT SCIENCE AND TECHNOLOGY, 17, 6, 1456, 1469, Jun. 2006, [Peer-reviewed]
English, Scientific journal - Morphodynamic modeling of sand bar evolution under unsteady flow
K. Kobayashi; Y. Shimizu; S. Giri; Y. Watanabe
RIVER FLOW 2006, VOLS 1 AND 2, 1221, +, 2006, [Peer-reviewed]
English, International conference proceedings - An Outline of Heavy Rainfall Disasters in Hidaka Region, Hokkaido Caused by Typhoon No. 10 in 2003
K. Hasegawa; T. Araya; T. Ogawa; S. Kikuchi; M. Kuroki; T. Komatsu; H. Saga; Y. Shimizu; O. Shimizu; H. Suzuki; Y. Suzuki; G. Tanaka; H. Tanaka; S. Tohma; M. Nakatsugawa; S. Hatta; Y. Murakami; T. Yamashita; T. Yamada; Y. Watanabe; Y. Watanabe; M. Fujita
Journal of Hydroscience and Hydraulic Engineering, 42, 1, 41, 56, 2006, [Peer-reviewed]
English, International conference proceedings - ジェットの着水過程における局所自由水面及び渦のダイナミクス
渡部靖憲; 猿渡亜由未
海岸工学論文集, 53, 1, 71, 75, 2006, [Peer-reviewed]
Japanese, Scientific journal - Numerical method to impose free-surface boundary conditions for local free-surface flows
Ayumi Saruwatari; Yasunori Watanabe
Advances in Hydro-science and -Eng., 7, 1860/732, 2006, [Peer-reviewed]
English, International conference proceedings - 小規模河床波上の流体-浮遊砂速度の同時PIV計測
秩父 宏太郎; 山下 智子; 渡部 靖憲
応用力学論文集, 9, 659, 666, 土木学会, 2006, [Peer-reviewed]
Japanese - 砕波帯流体運動のLarge Eddy Simulationの底面境界条件依存性とTwo Layer Modelの適用
渡部靖憲; 樫野英之; 大島香織
海洋開発論文集, 21, 283, 288, 2005
Scientific journal - Mechanisms to Form Wave Pressure at Walls under Jets
Yasunori Watanabe; Takayuki Otomo; Ayumi Saruwatari
Journal of coastal engineering, JSCE, 52, 1, 736, 740, 2005, [Peer-reviewed]
Japanese, Scientific journal - AN OUTLINE OF HEAVY RAINFALL DISASTERS IN HIDAKA REGION, HOKKAIDO, BY TYPHOON NO.10, 2003
HASEGAWA Kazuyoshi; SUZUKI Hiroyuki; SUZUKI Yuichi; TANAKA Gaku; TANAKA Hitoshi; TOHMA Satoshi; NAKATSUGAWA Makoto; HATTA Shigemi; MURAKAMI Yasuhiro; YAMASHITA Toshiko; YAMADA Takashi; ARAYAE Tohru; WATANABE Yasuharu; WATANABE Yasunori; FUJITA Mutsuhiro; OGAWA Takehiro; KIKUCHI Shunichi; KUROKI Mikio; KOMATSU Toshimitsu; SAGA Hiroshi; SHIMIZU Osamu
PROCEEDINGS OF HYDRAULIC ENGINEERING, 49, 49, 427, 432, Japan Society of Civil Engineers, 2005, [Peer-reviewed]
Japanese, The typhoon No.10 hit the Pacific cost in Hokkaido on August 9 in 2003. The casualties were 10 killed and 3 wounded. The missing person has not been found yet. This typhoon gave the biggest damage by flood to Hokkaido in the last twenty years. In Saru River basin and Appetu River basin in Ilidaka region, serious damages, such as flooded house, house failure and bridge fall, occurred by this typhoon. Farmland and flood plain were covered for the large sediment.
In this paper, we will report an outline of heavy rainfall disasters of Hidaka region in Hokkaido by the typhoon No.10. We hope that the result of this investigation helps to clarify the mechanisms of the heavy rainfall disasters with hydrologic and hydraulic knowledge. - Three-dimensional vortex structures under breaking waves
Watanabe Yasunori; Saeki Hiroshi; Hosking Roger J.
Journal of Fluid Mechanics, 545, 545, 291, 328, Cambridge University Press, 2005, [Peer-reviewed]
English, Scientific journal - Air-bubbles entraining and trapping within large-scale vortices under breaking waves
WATANABE Y.
混相流, 18, 3, 巻頭, 15 Sep. 2004, [Peer-reviewed]
Japanese - INFRARED FIELD OBSERVATIONS ON AERATED AREA OF BREAKING WAVES IN THE SURF ZONE
MORI Nobuhito; WATANABE Yasunori
Doboku Gakkai Ronbunshu, 2004, 768, 101, 111, 土木学会, 21 Aug. 2004, [Peer-reviewed]
Japanese, Transition of infrared radiation on a sea surface is strongly influenced by reflection of sunlight and sea surface disturbances. The field measurements of breaking waves in surf zone were conducted by the highly sensitive infrared camera. The characteristic changes of infrared images due to bubble formation at the sea surface are discussed. The distinctive patterns of infrared images are associated with the incident wave phase and the wave breaking. The velocity fields on the sea surface are estimated by the PIV method and the correlation between the sea surface velocity and infrared image changes is discussed. The quantitative method to measure sea surface disturbance by the breaking wave is proposed using the infrared radiation image and image processing technique. - TRANSITIONS OF INFRARED RADIATION IN BREAKING WAVES, AND VISUALISASION FOR THE SUB-SURFACE STREAMWISE VORTEX STRUCTURES
WATANABE Yasunori; MORI Nobuhito
Doboku Gakkai Ronbunshu, 2004, 768, 89, 100, 土木学会, 21 Aug. 2004, [Peer-reviewed]
Japanese, Scientific journal, Large-scale vortex structures beneath a free-surface in breaking waves are visualised by a characteristic distribution of a surface temperature estimated by infra-red radiation in this paper. Counter-rotating streamwise vortices occurring at wave plunging disrupt a so-called skin layer on the surface to entrain into bulk water underneath the layer. Because of a distinctive difference in temperature between the skin layer and bulk water, the spatial distribution of the surface temperature reflects the intensity of local water mixing on the surface due to the sub-surface stream-wise vortices. Typical length- and time- scales of the stream-wise vortices are determined throughout a surf-zone by utilizing a temperature spectrum and its temporal variation on the basis of the infrared measurements. - Bubble sizing and counting in a surf zone by an acoustic technique
Yasunori Watanabe; Yuji Yamauchi; Hiroshi Saeki
Asian and Pacific Coasts, 2003 - Proceedings of the 2nd International Conference, 2004
International conference proceedings - ESTIMATION AND COUNTERMEASURE ON ABRASION OF OFFSHORE STRUCTURE MADE OF CONCRETE DUE TO SEA ICE MOVEMENT
TAKEUCHI Takahiro; NAKAZAWA Naoki; MIKAMI Takashi; WATANABE Yasunori; SAEKI Hiroshi
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 20, 20, 1223, 1227, Japan Society of Civil Engineers, 2004, [Peer-reviewed]
Japanese, Offshore structure made of concrete in ice-covered sea areas is likely to meet an abrasion due to sea ice movement, and needs to be a light weight because of long carriage for its installation. Therefore, it is necessary to determine the thickness of covered concrete with high accuracy. The method to estimate an amount and area of abrasion is shown in considering both local ice pressure distribution and change of water level due to tide. The way to reduce the abrasion is also proposed. - FIELD OBSERVATION OF MOORED FISHING BOAT MOTIONS USING A 3D PTV ALGORITHM
SATO Noriyuki; WATANABE Yasunori; HIDESHIMA Yoshiyasu; KONDO Hirofumi; SAEKI Hiroshi
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 20, 20, 1305, 1310, Japan Society of Civil Engineers, 2004, [Peer-reviewed]
Japanese, The field measurement of moored ship motions is necessary to decrease troubles in cargo handling. But it was difficult to measure ship motions accurately by using accelerometer.
In this paper, a 3D PTV algorithm is applied to field observation of moored fishing boat motions. As a result, six-directional ship motions are measured accurately. This observation shows that heaving, rolling and pitching have only one energy peak which is the same period as energy peak of sea wave. Surging, swaying and yawing have two energy peaks, and the energy of peak in long period is higher than the energy of peak in short period. These two peaks are the same period as peaks of sea wave. - 砕波に伴う非回転流速場から回転流速場への遷移に関する研究
渡部 靖憲; 樫野 英之; 佐伯 浩
海岸工学論文集, 51, 51, 101, 105, 公益社団法人 土木学会, 2004, [Peer-reviewed]
Japanese, この論文では, 粘性, 乱れを考慮した波動下の流速場の数値計算結果を回転, 非回転流れに分離し, 砕波に伴う非回転流速場から回転流速揚への遷移について調べられている.砕波点を境に非回転運動エネルギーの一部は回転運動エネルギーへと遷移し, さらに小スケール乱れへとエネルギーを受け渡す.回転流れ中の歪み率は非回転流れのそれより非常に強く乱れ生成と密接な関係をもつため, 乱れを適当に考慮した砕波モデルを考える場合にはこの回転流れの評価が重要になる. - 三次元Super-Resolution PIV の開発と砕波下の混相流への適用
渡部 靖憲; 秀島 賢保; 佐伯 浩
海岸工学論文集, 51, 51, 106, 110, 公益社団法人 土木学会, 2004, [Peer-reviewed]
Japanese, この論文は, 低計算コスト, 高精度, 高解像度で三次元粒子速度を取得可能な三次元Super-Resolution PIVを提案し, 計測精度及びその粒子数依存性を検証し工学的問題への適用性について議論するものである.また, 大規模渦モデルの速度場における本PIVシステムの解析と数値試験の解析解との比較を行い, その実践的適用性を検証すると共に, 砕波後に生成された大規模渦が海底砂を巻き上げる際に形成される混相乱流に対してもこのPIV法を適用し, 砕波通過後の流体, 固体両相の三次元速度分布の時間変化について議論される. - 3-D EDDY STRUCTURE AROUND the BREAKWATER HEAD with WAVE OVERTOPPING
Masaya Kato; Yasunori Watanabe; Hiroshi Saeki
Proceedings of the Coastal Engineering Conference, 2003-, 1661, 1670, American Society of Civil Engineers (ASCE), 2003
English, International conference proceedings - 3DPTV for a large domain and its application to large-scale turbulence
WATANABE Yasunori
可視化情報学会誌 = Journal of the Visualization Society of Japan, 22, 0, 383, 384, The Visualization Society of Japan, 01 Jul. 2002, [Peer-reviewed]
Japanese, Lagrangian fluid motion under breaking waves and settling motion of glass-particles released into a still water are measured by the 3D stereoscopic particle tracking velocimetry for a large domain (3DSPTV-LD). Since the 3DSPTV-LD dose not require to use a laser sheet for illuminating a single flow plane in a measur domain, it has an advantageous feature in engineering use -i.e. high applicability to 3D measurementsfor a large domain on less costs. In coastal engineering, the large-scale turbulence associated with a large-scale eddy structur, such as a separated vortex array around a structure, which futures three-dimensional behav-iora.is one of the crucial factors affecting sediment transport and stability of a structurc.The 3DSPTV-LD enables it to acquire the 3D large-scale Lagrangian motion over a wide area. - Velocity field after wave breaking
Y Watanabe; H Saeki
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, 39, 7, 607, 637, Jul. 2002
English, Scientific journal - An Experimental Study on 3-D Fluid Motion in the Pore of Block-Type Submerged Breakwater under Waves
重松孝昌; 渡部靖憲; 竹原幸生; 奥村悠樹; 小池敏也
土木学会・海岸工学論文集, 49, 1, 791, 795, 2002
Scientific journal - Experimental Study on Benthic Fish Habitats in an Ice Covered River
T. Nogami; Y. Watanabe; M. Nakatsugawa; F. Nakamura; K. Kamura; H. Yamada; S. Tsuchiya; K. Watanabe; H. Iwase
Ice in the Environment: Proc. of the 16th IAHR International Symposium on Ice, Dunedin, International Association of Hydraulic Engineering and Research, 104, 110, 2002, [Peer-reviewed]
Scientific journal - Field Experiments for Mitigation Benthic Fish Habitats in the Makomanai River
T. Nogami; Y. Watanabe; M. Nakatsugawa; F. Nakamura; K. Kamura; H. Yamada; S. Tsuchiya; K. Watanabe; H. Iwase
River Flow 2002, 541, 549, 2002, [Peer-reviewed]
Scientific journal - 砕波遷移に伴う気泡生成特性変化とマイクロバブル量に関する研究
渡部 靖憲; 山内 悠司; 佐伯 浩
海岸工学論文集, 49, 49, 106, 110, 公益社団法人 土木学会, 2002, [Peer-reviewed]
Japanese, この論文は, 北海道石狩浜における現地実験 (2001.10.4) 及び室内実験を通して砕波帯に浮遊, 滞留する微細気泡量の岸沖分布を計測し, 水面の安定度に対する微細気泡生成の依存性を調べると共に, ハイドロフォンにより砕波下に発生した気泡音を受信することで, 気泡音の周波数解析を基本とした砕波後の生成気泡サイズ, 気泡数の時空間変化を特徴化し流体運動との関係を明らかにしようとするものである.さらに界面活性効果による気泡生成への依存性についても議論を行っている. - 直立堤堤頭部近傍の局所流体力特性
加藤 雅也; 渡部 靖憲; 佐伯 浩
海岸工学論文集, 49, 49, 716, 720, 公益社団法人 土木学会, 2002, [Peer-reviewed]
Japanese, ケーソン式混成堤の堤頭部では, 剥離を伴う複雑な三次元渦構造が形成されている. そのため, 堤頭部における被覆材の散乱は, 堤幹部における場合とは異なる複雑なメカニズムを有していると考えられる. 本研究では, 直立堤堤頭部周辺の流速場をLarge Eddy Simulationによりシミュレートし, 得られた水理量を用いて局所流体力特性の空間変動特性を調べた. その結果, 開口率の小さな中小規模港湾に対して現行設計法によりマウンド被覆材所要質量を算定した場合, 被覆材の質量が不足する可能性があることを示した. また, 堤頭部近傍では加速度の増幅効果によって, 慣性力の寄与が著しく大きくなる場合があることを明らかにした. - 波動乱流境界層の三次元化と乱流拡散に関する研究
渡部 靖憲; 松本 卓; 佐伯 浩
海岸工学論文集, 49, 49, 76, 80, 公益社団法人 土木学会, 2002, [Peer-reviewed]
Japanese, この論文は, 二次元乱流波動境界層の三次元遷移と海底地形変動機構について論じるものである.三次元的海底地形の顕著な例であるbrick-pattern砂漣の形成の原因となる二次元砂漣上の流れの三次元不安定から発達する有意な三次元組織渦構造が三次元Large Eddy Simulationによって計算され, 海底面から放出されるpassive scalar関数の移流拡散過程が調べられている.移動床実験による海底形状と乱れ剪断力の二次元波数スペクトル解析が行われ, 卓越波数の相関について議論される. - Large-eddy simulation of local flows around the head of a breakwater
Masaya Kato; Yuhki Okumura; Yasunori Watanabe; Hiroshi Saeki
Proceedings of the International Symposium on Ocean Wave Measurement and Analysis, 2, 1126, 1135, 01 Dec. 2001
International conference proceedings - Evolution of bubbly flow in the surf zone
Yasunori Watanabe; Junichi Ohtsuka; Hiroshi Saeki
Proceedings of the International Symposium on Ocean Wave Measurement and Analysis, 2, 992, 1001, 01 Dec. 2001
International conference proceedings - Stability of armor units for a leeward mound of composite breakwaters
Tetsuya Hayakawa; Yasuji Yamamoto; Katsutoshi Kimura; Yasunori Watanabe
Proceedings of the International Symposium on Ocean Wave Measurement and Analysis, 2, 1755, 1762, 2001
International conference proceedings - EFFICIENCIES OF THE PRACTICAL NUMERICAL METHOD FOR SIMULATIONS OF WAVE AND VELOCITY FIELD
WATANABE Yasunori; KATO Masaya; YASUHARA Mikio; SAEKI Hiroshi
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 17, 17, 287, 292, Japan Society of Civil Engineers, 2001
The Multigrid method (MG) was applied to the 2D and 3D simulations for water waves on various topographies, and the efficiency in terms of computation speed was discussed in this paper. Purpose of this paper is to remove the limitation of computational costs for numerical investigations by introducing MG and to evaluate the availability of this numerical method for practical estimations in the actual wave field. The computational time and number of iteration that MG requires is quantitatively compared with the conventional Gauss-Seidel method (GS). It is found that the MG makes the computational time to save 90-95% for the two-dimensional simulation and 65-80 % for the three-dimensional simulation. Further improvement of the scheme is also discussed in this paper. - Field Experiments on Sink-and-Float Type Ice Boom (SFIB) In Saroma Lagoon
SAEKI Hiroshi; KAWAI Kunihiro; WATANABE Yasunori; TACHIBANA Harukuni; IMAIZUMI Akira; MATSUO Yuuko
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 17, 17, 583, 587, Japan Society of Civil Engineers, 2001
This is a report on the results of experiments aimed to clarfy the optimal section form of sink-and-float type ice boom (SFIB) which may prevent SFIB from becoming buried in send when it sinks and on the results of in site tests at Saroma Lagoon which is located on the Okhotusk sea coast of Hokkaido. - 砕波帯内の3次元流速の実験的評価:拡張型3次元ステレオグラムPTVの開発と応用
奥村 悠樹; 渡部 靖憲; 加藤 雅也; 佐伯 浩
海岸工学論文集, 48, 48, 96, 100, 公益社団法人 土木学会, 2001
Japanese - Advanced numerical method for a practical simulation of water waves
Y Watanabe; M Kato; M Yasuhara; Y Okumura; H Saeki
PROCEEDINGS OF THE FIRST ASIAN AND PACIFIC COASTAL ENGINEERING CONFERENCE, VOLS 1 AND 2 (APACE 2001), 96, 105, 2001, [Peer-reviewed]
English, International conference proceedings - Three-dimensional measurements of fluid motion under waves
Y Watanabe; Y Okumura; M Kato; H Saeki
PROCEEDINGS OF THE FIRST ASIAN AND PACIFIC COASTAL ENGINEERING CONFERENCE, VOLS 1 AND 2 (APACE 2001), 126, 135, 2001, [Peer-reviewed]
English, International conference proceedings - Three-dimensional large-scale eddies of breaking waves
Yasunori Watanabe; Mikio Yasuhara; Hiroshi Saeki
Coastal Engineering 2000 - Proceedings of the 27th International Conference on Coastal Engineering, ICCE 2000, 276, 942, 952, 01 Dec. 2000
International conference proceedings - 実海域における砕波に伴う気泡生成及び連行特性
渡部 靖憲; 大塚 淳一; 安原 幹雄; 加藤 雅也; 王 毅; 佐伯 浩
海岸工学論文集, 47, 47, 131, 135, 公益社団法人 土木学会, 2000
Japanese - 直立堤堤頭部周辺の流動構造に関する3次元数値シミュレーション
加藤 雅也; 奥村 悠樹; 渡部 靖憲; 佐伯 浩
海岸工学論文集, 47, 47, 776, 780, 公益社団法人 土木学会, 2000
Japanese - NUMERICAL SIMULATION OF FLOW PATTERN AROUND A HORIZONTAL PLATE IN WAVE FIELD
KATO Masaya; WATANABE Yasunori; SAEKI Hiroshi
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 16, 16, 75, 80, Japan Society of Civil Engineers, 2000, [Peer-reviewed]
The horizontal plate has usually been used for coastal and ocean structures, such as an upper slab of pier and a buffer structure around a bridge pier. And there have been also a lot of research on the use of horizontal plate for submerged breakwater against beach erosion and artificial sea bed for the fish-raising industry. Much effort has so far been devoted to the research of wave fields around a horizontal plate, especially about the impact force to pier and the wave deformation around submerged horizontal plate in terms of the design for the structure. However, the flow pattern around horizontal plate in a wave field has not been explicated. The current study has attempted to numerically analyze some of the wave fields around a horizontal plate. Based on the results of this study, this paper discusses the characteristics of the evolution process of fluid motion and eddy motion around a horizontal plate. - Evaluation of ice forces acting on sea bed due to ice scouring
S Kioka; Y Yasunaga; Y Watanabe; H Saeki
PROCEEDINGS OF THE 10TH (2000) INTERNATIONAL OFFSHORE AND POLAR ENGINEERING CONFERENCE, VOL I, 1, 749, 755, 2000
English, International conference proceedings - THREE-DIMENSIONAL LARGE EDDY SIMULATION OF BREAKING WAVES
WATANABE Yasunori; SAEKI Hiroshi
Coast. Eng. J., 41, 3, 281, 301, 01 Dec. 1999, [Peer-reviewed]
English, Scientific journal - STABILITY OF ARMOR UNITS ON A HARBOR-SIDE MOUND AGAINST WAVE OVERTOPPING WITH BACKWARD PARAPETS
HAYAKAWA Tetsuya; KIMURA Katsutoshi; HAYASHI Tadashi; DOI Yoshikazu; WATANABE Yasunori
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 15, 15, 713, 717, Japan Society of Civil Engineers, 1999, [Peer-reviewed]
Japanese, The high mound is sometimes constructed behind a composite breakwater in order to increase the sliding resistance and utilize the mound for an aquacultural purpose. The high mound must be covered by armor units with adequate weight to prevent from scattering by overtopping waves. However, the shallower is the submerged depth of the mound, the heavier become the armor units.
This study proposed a backward parapet as a countermeasure to reduce weight of armor units. A numerical simulation showed the difference in the velocity field behind the caisson between the backward and forward parapet. With the backward parapet, large-scale eddies were not observed and the velocity on the mound was slower than that of the forward parapet. Furthermore, hydraulic model tests showed that the stable weight was approximately 40% less than that of the forward parapet. - STABILITY OF ARMOR UNITS ON A HARBOR-SIDE MOUND AGAINST WAVE OVERTOPPING WITH BACKWARD PARAPETS
HAYAKAWA Tetsuya; KIMURA Katsutoshi; HAYASHI Tadashi; DOI Yoshikazu; WATANABE Yasunori
Doboku Gakkai Ronbunshuu B, 15, 713, 717, 土木学会, 1999
The high mound is sometimes constructed behind a composite breakwater in order to increase the sliding resistance and utilize the mound for an aquacultural purpose. The high mound must be covered by armor units with adequate weight to prevent from scattering by overtopping waves. However, the shallower is the submerged depth of the mound, the heavier become the armor units.<BR>This study proposed a backward parapet as a countermeasure to reduce weight of armor units. A numerical simulation showed the difference in the velocity field behind the caisson between the backward and forward parapet. With the backward parapet, large-scale eddies were not observed and the velocity on the mound was slower than that of the forward parapet. Furthermore, hydraulic model tests showed that the stable weight was approximately 40% less than that of the forward parapet. - PERMEATION OF SPILLED CRUDE OIL INTO SEA ICE SHEET
OHSHIMA Kaori; OHTSUKA Natsuhiko; ISHIKAWA Hiroki; TAKAHASI Shinjiro; WATANABE Yasunori; TATIBANA Naokuni; SAEKI Hiroshi
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 15, 15, 559, 564, Japan Society of Civil Engineers, 1999, [Peer-reviewed]
Development of oil and gas deposits off Sakhalin's northern coast in the sea of Okhotsk are currently under way.An accident involving a spill of crude oil could be expected to affectthe environment and economy of the Hokkaido's Okhotsk coast.If the oil spill occurred in winter season due to the accidents of pipeline, oil tanker and oil rigs, spilled oil would be trapped under the ice floes. If the operation for recovery of spilled oil will be late, spilled oil under the ice floes will be trapped in the ice sheet. In this paper the authors report the behavior of spilled oil trapped under ice sheet and the permeation of spilled oil into ice sheet. - NUMERICAL SIMULATION OF THE IMPACT BREAKING WAVE FORCE ACTING ON THE BREAKWATER
WATANABE Yasunori; MATSUMOTO Yasuharu; HAYAKAWA Tetsuya; WANG Yi; OHTSUKA Jun-ichi; YASUHARA Mikio; SAEKI Hiroshi
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 15, 15, 375, 380, Japan Society of Civil Engineers, 1999, [Peer-reviewed]
When the overturning jet of broken wave hits a wall of coastal structure such as a breakwater, the impact force acts on the structure, which often give a great damage to the structure. Although there have been many reports on the impact force, little is known about the quantitative properties of the force and velocity fluctuation in time. In this paper, the plunging jet attacking to the structure was numerically solved by the direct numerical scheme with the high level of accuracy. The correlations between the surface profiles, the direction of fluid velocity and the pressure were also discussed through the investigations of spatial and temporal changes of them. - Generation and Motion of the Air Bubbles Entrained by the Jet.
渡部靖憲; 大塚淳一; 佐伯浩
海岸工学論文集, 46, 46, 116, 120, 公益社団法人 土木学会, 1999, [Peer-reviewed]
Japanese - Evolution of Three-Dimensional Large-Scale Swirl Eddies, Oblique Eddies and Plunging Jets.
渡部靖憲; 安原幹雄; 佐伯浩
海岸工学論文集, 46, 46, 141, 145, 公益社団法人 土木学会, 1999, [Peer-reviewed]
Japanese - Numerical Study on the Evolution of Eddies and Surface Variations Caused by Wave Overtopping.
渡部靖憲; WANG Y; 早川哲也; 佐伯浩
海岸工学論文集, 46, 46, 741, 745, 公益社団法人 土木学会, 1999, [Peer-reviewed]
Japanese - Development of Recovery Methods for Spilled Oil under Ice Floes
Ohshima Kaori; Usami Norihiro; Takahashi Shinjiro; Kawai Kunihiro; Ohtsuka Natsuhiko; Watanabe Yasunori; Saeki Hiroshi
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 14, 14, 435, 439, Japan Society of Civil Engineers, 1998
Development of oil and natural gas deposits off Sakhalin's northern coast on the Sea of Okhotsk are currently under way. Should an accident involving a spill of crude oil or other effluents occur during the development of the oil and natural gas deposits that is currently under way off the eastern coast of northern Sakhalin, it can be expected to have an impact on the environment and economy of the Hokkaido's Okhotsk Sea and Pacific Ocean coast. This paper describes the recovery method for spilled oil under ice floes through the systematic experiments. - Experimental Study on Three Dimensional Fluid Motion in a Surf Zone.
渡部靖憲; 松本靖治; 佐伯浩
海岸工学論文集, 45, 45, 136, 140, 公益社団法人 土木学会, 1998, [Peer-reviewed]
Japanese - 砕波の3次元Large Eddy Simulation
渡部 靖憲; 森 憲広; 佐伯 浩
海岸工学論文集, 45, 45, 146, 150, 公益社団法人 土木学会, 1998, [Peer-reviewed]
Japanese - Characteristics of Reynolds Stress and Turbulent Energy Variation after Wave Breaking.
渡部靖憲; 梅田克史; 佐伯浩
海岸工学論文集, 45, 45, 121, 125, 公益社団法人 土木学会, 1998, [Peer-reviewed]
Japanese - Armor Stability of Leeside Mound of Composite Breakwater against Wave Overtopping.
早川哲也; 渡部靖憲; 鈴木孝信; 木村克俊; 土井善和; 工藤貴弘
海岸工学論文集, 45, 2, 691, 695, 土木学会, 1998
Japanese, 混成堤の基礎捨石マウンドは来襲波浪による散乱や変形を生じないように十分な重量を有する石やコンクリートブロックにより被覆される.防波堤港外側のマウンド被覆材については,谷本ら(1982)や高橋ら(1990)により十分な検討が行われており,設計波浪に対して適切な重量を算定することができる.また,近年では須藤ら(1995)により変形を許容した重量算定法も提案されており,マウンド機能を損なわない程度に重量を低減することができる.これに対して,港内側のマウンド被覆材については港外側重量の25～50%の値が経験的に使用されている.しかしながら,実際には被災事例は極めて少なく,条件によっては被覆工が省略でき工費の縮減が可能になると考えられる.さらに,図-1に示すように防波堤港内側の静穏域に浚渫土砂などの安価な資材を用い藻場造成を目的としたマウンド部を設け,水産生物の生息場として利用する計画がある.この場合,コンブ等が光合成を十分に行えるように,マウンド天端水深を4～5m程度とするため,越波水の打ち込みに対する被覆材の安定性の検討が重要な課題となる.そこで本研究では数値計算および水理模型実験により越波水の打ち込み特性と港内側マウンド被覆材の安定性についての検討を行った.これらの結果により被覆材の移動特性を明らかにするとともに安定重量の算定法を提案する. - Abrasion of various materials used in offshore structures due to a movement of ice sheet
Takashi Terashima; Fumihiro Hara; Kiyoshi Miyatake; Yasunori Watanabe; Hideki Honda; Hiroshi Saeki
Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 01 Jan. 1998 - Control and recovery of spilled oil by using ice boom
S Takahashi; K Ohshima; K Kawai; Y Watanabe; H Saeki
OIL AND HYDROCARBON SPILLS, MODELLING, ANALYSIS AND CONTROL, 333, 345, 1998
English, International conference proceedings - 混成堤における越波水の打ち込み特性と被覆材の安定性
早川 哲也; 渡部 靖憲; 鈴木 孝信; 木村 克俊; 土井 善和; 工藤 貴弘
海岸工学論文集, 45, 45, 691, 695, 土木学会, 1998, [Peer-reviewed]
Japanese, 混成堤の基礎捨石マウンドは来襲波浪による散乱や変形を生じないように十分な重量を有する石やコンクリートブロックにより被覆される.防波堤港外側のマウンド被覆材については，谷本ら(1982)や高橋ら(1990)により十分な検討が行われており，設計波浪に対して適切な重量を算定することができる.また，近年では須藤ら(1995)により変形を許容した重量算定法も提案されており，マウンド機能を損なわない程度に重量を低減することができる.これに対して，港内側のマウンド被覆材については港外側重量の25～50%の値が経験的に使用されている.しかしながら，実際には被災事例は極めて少なく，条件によっては被覆工が省略でき工費の縮減が可能になると考えられる.さらに，図-1に示すように防波堤港内側の静穏域に浚渫土砂などの安価な資材を用い藻場造成を目的としたマウンド部を設け，水産生物の生息場として利用する計画がある.この場合，コンブ等が光合成を十分に行えるように，マウンド天端水深を4～5m程度とするため，越波水の打ち込みに対する被覆材の安定性の検討が重要な課題となる.そこで本研究では数値計算および水理模型実験により越波水の打ち込み特性と港内側マウンド被覆材の安定性についての検討を行った.これらの結果により被覆材の移動特性を明らかにするとともに安定重量の算定法を提案する. - Mean Flow Velocity and Scale of Fluid Motion in the Surf Zone.
渡部靖憲; 森憲広; 稲垣啓; 佐伯浩
海岸工学論文集, 44, 44, 121, 125, 公益社団法人 土木学会, 1997
Japanese - Study on Three-dimensional Erosion of a Sandy Bed due to Undertow and on Velocity of Suspened Ssediment
Watanabe Yasunori; Saeki Hiroshi; Mori Norihiro; Inagaki Kei
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 13, 13, 865, 870, Japan Society of Civil Engineers, 1997, [Peer-reviewed]
The velocity field in a surf zone was experimentally investigated, and the effects of an undertow after wavebreaking on turbulence and wave motion are discussed. In order to reveal the mechanisms of sand suspension overthe bottom, the measurement of velocity distribution of sand transportation was tried by the particle imagevelocimetry.
It is important to understand the reciprocal relationship between turbulence caused by wave breaking anda cross-shore steady flow, such as a rip current or an undertow, as both of these are closely related to sedimentrolling up and cross-shore sediment transport. On the other hand, high-strain turbulent flows that have threedimensionallycoherent eddy structures with oblique vortexes are generated in a surf zone, and the steady flow isstrongly influenced by the three-dimensional vortexes generated at thistime. This study was designed to investigatethe three-dimensional characteristics of the velocity field and bed erosion in a surf zone, and the effects of undertowon them, of undertow on them, in order to clarify the mechanisms of fluid motion and the cross-shore sedimenttransport in this region. - Stability of Armor Stones on Doubly Placed Submerged Breakwaters Due to Ice Floes Action in Wave Field
Hayakawa T.; Kitamura T.; Sato M.; Kinosita C.; Watanabe Y.; Saeki H.
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 13, 13, 837, 842, Japan Society of Civil Engineers, 1997, [Peer-reviewed]
It is cralified that doubly placed submerged break waters reduce the incident wave height effectively where the tidal range is small.
Coastal structures constracted in Ohotuku Sea coast of Hokkaido have been attacked by water waves and drifting ice floes. In this paper, the authors cralified the stability of armor stones on doubly placed submerged breakwaters whitch are attacked by waves and ice floes through systematic experiments. - Three-dimensional characteristics of velocity field and effects of undertow in a surf zone
Y Watanabe; N Mori
PROCEEDINGS OF THE SEVENTH (1997) INTERNATIONAL OFFSHORE AND POLAR ENGINEERING CONFERENCE, VOL III, 1997, 3, 247, 253, 1997
English, International conference proceedings - Direct simulation of velocity field in surf-zone.
渡部靖憲; 佐拍浩
海岸工学論文集, 43, 43, 71, 75, 公益社団法人 土木学会, 1996
Japanese - Hydrodynamic force accompanied by the detachment on the surface of a column in horizontal vibration.
佐藤幸雄; 渡部靖憲
海岸工学論文集, 43, 43, 911, 915, 公益社団法人 土木学会, 1996
Japanese - Numerical analysis of breaking waves
Y Watanabe; H Saeki
HYDRAULIC ENGINEERING SOFTWARE VI, 385, 394, 1996, [Peer-reviewed]
English, International conference proceedings - Mean Flow and Turbulence in a Surf Zone
Watanabe Yasunori; Mori Norihiro; Kuroki Mikio; Saeki Hirosi
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 12, 12, 37, 42, Japan Society of Civil Engineers, 1996, [Peer-reviewed]
Three-dimensional fluid velocity field in a surf zone was experimentally investigated to obtain spatial characteristics of mean flow, such as return current, and turbulence flow caused by wave breaking. It is possible that three-dimensional organized vorticities, generated after breaking, indirectly affect to mean flow and induce three-dimensional steady flow. In two-dimensional wave flume, return current contributes three-dimensionality of fluid motion in a surf zone. The effect of return current to a front bore is also investigated by the particle image velocimetry. - Vertical Ice Forces on Pile Structures and Its Design Method
Terashima Takashi; Nakazawa Naoki; Kioka Shinji; Watanabe Yasunori; Saeki Hiroshi
Doboku Gakkai Ronbunshuu B, 11, 235, 239, Japan Society of Civil Engineers, 1995 - On the application of Modified Green function for wave field.
Orihashi Tsuneharu; Watanabe Yasunori; Hamanaka Ken-ichiro
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 11, 11, 1, 6, Japan Society of Civil Engineers, 1995
For the problem of diffraction and radiation of water waves from an arbitrary shapcd body, John's Green function (1950) has been used by several authors. However this John's Green function seems to have a ill behavior when the problem solved numerically through discretization.In this paper we point out that this ill behavior is caused from the definition of delta function which is used by John, and propose a new Green function as a Modified Green function, and check the application of this Green function for wave field. - On the Effect of Return Current to Inner Velocity Field of Breaking Wave
Watanabe Yasunori; Hosokawa Hiroki; Saeki Hiroshi
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 11, 11, 19, 24, Japan Society of Civil Engineers, 1995
The phisical characterristics of breaking wave are investigated in cases of permitting to occur the return current and compulsorily removing it.Breaking wave motion is complicated by variety factors and connecting them.Effective one of these factors is return current which have a large scale effect compair with other factors as viscosity, capiraly stress, and turbulent. Therefore it is very important to investigate how the return current affect to the inner velocity field at breaking.Since the fluid motion is temporally and spacially unsteady in the breaking zoon, the messurement of fluid motion should be carry out in the view of these aspects.In this paper, the inner velocity at breaking is spacially investigated by perticle image velocimeter.Especially, we could understand that the structure of fluid motion is sufferd by the return current. - Safety for Utilization of Sea Ice Cover
Okubo Yasuhiro; Watanabe Yasunori; Kioka Sinji; Saeki Hiroshi
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 11, 11, 283, 286, Japan Society of Civil Engineers, 1995
Nowadays people enjoy a variety of sports and recreations on frozen surfaces in winter. It is important to estimate the bearing capacity of an infinite ice sheet in order to ensure their safety. In this study, (1) we show in charts and graphs the estimated bearing capacity of ice sheets obtained by the deflection of ice sheets per unit load without breaking the ice; (2) we obtain an equation to calculate the bearing capacity of ice sheets with holes and indicate the results in charts; and (3) we describe in charts the critical traveling speed of loads moving on ice sheet when the bearing capacity is at minimum. - NUMERICAL STUDY ON THE ENERGY-LOSS AND THE WAVE ATTENUATION OVER THE RIPPLED BED
Y WATANABE; H SAEKI; K HAMANAKA
PROCEEDINGS OF THE FIFTH (1995) INTERNATIONAL OFFSHORE AND POLAR ENGINEERING CONFERENCE, VOL III, 1995-June, 64, 69, 1995, [Peer-reviewed]
English, International conference proceedings - Flow structure around column in wave field.
奥村慎也; 佐藤幸雄; 渡部靖憲
海岸工学論文集, 42, 42, 831, 835, 公益社団法人 土木学会, 1995, [Peer-reviewed]
Japanese - Analysis of motion mechanism in breaking wave zone with image processing.
渡部靖憲; 佐伯浩
海岸工学論文集, 42, 42, 116, 120, 公益社団法人 土木学会, 1995, [Peer-reviewed]
Japanese - Calculation method of inner flow rate of nonlinear wave.
渡部靖憲; 細川裕希; 佐伯浩
海岸工学論文集, 42, 42, 106, 109, 公益社団法人 土木学会, 1995, [Peer-reviewed]
Japanese - Modified Green functions in wave field.
折橋恒春; 渡部靖憲; 浜中建一郎
海岸工学論文集, 41, 41, 26, 30, 公益社団法人 土木学会, 1994, [Peer-reviewed]
Japanese - Numerical analysis of oscillatory flow around a circular cylinder
Y. Watanabe; T. Orihashi; K. Hamanaka; Y. Sato
National Conference Publication - Institution of Engineers, Australia, 1, 93 pt 4, 229, 234, 01 Jan. 1993
International conference proceedings - 全天候バースにおける空気流動の特性
近藤よし郎; 渡部靖憲; 山上佳範; 杉岡一郎
海岸工学論文集, 39, 2, 1061, 1065, Japan Society of Civil Engineers, Nov. 1992
Japanese - Variation of Inner Pressure in Caisson Type Structure due to Ice Growth.
ISHII CHIMATARO; SATO HIDEYASU; ORITANI NORIHIRO; WATANABE YASUNORI; SAEKI HIROSHI; YAMASHITA TOSHIHIKO
海洋開発論文集, 8, 195, 199, Japan Society of Civil Engineers, 1992
Japanese, Recently, caisson type structures have been employed as offshore structures in regions of extreme cold. As the liquid, sand or gravel filling proceeds, the caisson freezes and the internal pressure rises. It has previously been verified that this pressure rise, due to an increase of volume caused by ice growth, depends strongly upon the permiability coefficient of the sea ice forming within the sands and gravels. This paper deals with the variation of inner pressure in two kinds of model caissons due to ice growth. - DESCRIPTIVE AND ANALYTICAL EPIDEMIOLOGY OF PEPTIC-ULCER DISEASE IN JAPAN
Y WATANABE; K KAWAI
GASTROENTEROLOGIA JAPONICA, 26, 258, 261, Jul. 1991, [Peer-reviewed]
English, Scientific journal - Large but variable particulate flux in the Antarctic Ocean and its significance for the chemistry of Antarctic water
Shizuo Tsunogai; Shinichiro Noriki; Koh Harada; Taro Kurosaki; Yasunori Watanabe; Masaru Maedaa
Journal of the Oceanographical Society of Japan, 42, 2, 83, 90, Apr. 1986
Scientific journal - Adsorption-desorption control of phosphate in anoxic sediment of a coastal sea, Funka Bay, Japan
Y. Watanabe; S. Tsunogai
Marine Chemistry, 15, 1, 71, 83, Aug. 1984
Scientific journal - Role of dissolved silicate in the occurrence of a phytoplankton bloom
Shizuo Tsunogai; Yasunori Watanabe
Journal of the Oceanographical Society of Japan, 39, 5, 231, 239, Oct. 1983
Scientific journal - Calcium in the North Pacific water and the effect of organic matter on the calcium-alkalinity relation
Shizuo Tsunogai; Yasunori Watanabe
GEOCHEMICAL JOURNAL, 15, 2, 95, 107, 1981
Scientific journal
- IR stereo reconstruction of water surface using temperature distribution induced by breaking waves
齋藤翔大; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Characterization of Suspended Solids Settling Properties in Effluent from Sewage Treatment
信時圭; 渡部靖憲; 中屋佑紀; 佐藤久, 日本水環境学会年会講演集, 59th, 2025 - Discussion on the Relationship Between 3D Wave Surfaces and Whitecap Coverage Derived from Stereo Images
粕谷有汰; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Influence of Heat Flux on Sea Ice on Sea Surface Pressure Wind Field under Bomb Cyclone
中村太洋; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Visualization of air density changes on breaking wave water surface
山崎浩太; 齋藤翔大; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Transition of Three-Dimensional Flow Structures in the Initial Stage of Wind Wave Development
中村颯; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Numerical calculation about Heat transfer through interface of scattered droplet
長田虎太朗; 猿渡亜由美; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Future Changes in Winter Explosive Cyclones passing over the Japan Sea and Sea of Okhotsk and Storm Surge Impacts
野村明弘; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Study on improving the accuracy of measuring bubble number density using multi-frequency ultrasound and cameras.
中山晴生; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Estimation of Suspended Sediment Concentration in the Surf Zone
戸谷魁斗; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Flows inside offshore breakwaters and energy dissipation
明石拓也; 渡部靖憲; 猿渡亜由美, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Tracking the time changes in particle size distribution using the moment method
宮崎一聡; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Fundamental Research Towards the Development of an Ultrasound Measurement Method for Bubbles in Seawater.
冨田大地; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - Measurement of Droplet Size and Velocity Distribution Using Laser Interferometry
兼安芳輝; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 81, 2025 - 最終沈殿池上澄水中の懸濁物質の沈降特性解析
信時圭; 渡部靖憲; 中屋佑紀; 佐藤久, 下水道研究発表会講演集, 62nd, 2025 - Enhancement of heat transfer from water surface to air by bubble bursting
齋藤翔大; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 80, 2024 - A STUSY OF CHARACTERISTICS OF COLLISION FORCE OF TSUNAMI DEBRIS SUCH AS SEA ICE FLOES ON A FLAT PLATE AND THEIR APPLICATION TO TSUNAMI FRAGILITY CURVE
木岡信治; 竹内貴弘; 渡部靖憲, 土木学会論文集(Web), 79, 18, 2023 - WAVE TRANSFORMATION THROUGH WAVE-VORTEX INTERACTIONS
渡部靖憲; 飯山侑; 三戸部佑太, 土木学会論文集(Web), 79, 17, 2023 - THREE-VIEW STEREO ANALYSIS FOR PLANAR WATER SURFACE MEASUREMENTS WITH PROJECTOR ILLUMINATION
三戸部佑太; 飯山侑; 渡部靖憲, 土木学会論文集(Web), 79, 17, 2023 - Development of three-dimensional wavefront observation method
粕谷有汰; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 79, 2023 - A study for measurement of the bubble size spectrum by a multi-frequency sonar
中山晴生; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 79, 2023 - Comparison of the whitecap coverage models in fetch-limited conditions
大和田宏太朗; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 79, 2023 - Measurement of the air temperature around an evaporating water
齋藤翔大; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 79, 2023 - FLUID MOTION DURING BUBBLE BURSTING PROCESSES IN PURE AND SEA WATER
渡部靖憲; 七澤梨花, 土木学会論文集 B2(海岸工学)(Web), 78, 2, 2022 - EVOLUTION OF THREE-DIMENSIONAL SURFACE FORMES OF INITIAL WIND WAVES
渡部靖憲; 黒田晴希, 土木学会論文集 B2(海岸工学)(Web), 78, 2, 2022 - A Proposal for Second-Order Accurate Pressure Extrapolation Calculation for Sharp Interface Model
土屋裕嵩; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 78, 2022 - Fundamental study on the bubbles bursting process
七澤梨花; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 78, 2022 - Spectral transitions of Faraday wave depending on excitation frequency
小嶋亮太; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 78, 2022 - Study of Wave packet focusing
小熊多佳史; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 78, 2022 - A Study of Wave Breaking Process by Directional Concentration Waves
藤澤蓮; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 78, 2022 - Visual Measurement of Three-Dimensional Water Surfaces Caused by Wind Waves
黒田晴希; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 78, 2022 - The research associated with velocity fluctuation of water particles in Faraday wave
小嶋亮太; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 77, 2021 - Numerical Simulation of Two-Layer Flow Using Sharp Interface Model
土屋裕嵩; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 77, 2021 - Wave packet focusing in the flow
小熊多佳史; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 77, 2021 - Surfactant effect on wave breaking entrained bubbles and residual foams
野中拓実; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 77, 2021 - Numerical modeling of floating bubbles remaining on the water surface
渡邊健太; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 77, 2021 - 波浪境界層内熱・運動量輸送のパラメタリゼーションと高潮高波災害評価
渡部靖憲, 京都大学防災研究所年報(Web), 64A, 2021 - Dynamic mode of internal waves induced by a typhoon passage
足立天翔; 猿渡亜由未; 宮武誠; 渡部靖憲, 混相流シンポジウム講演論文集(Web), 2019, ROMBUNNO.B212_0114 (WEB ONLY), 2019
Japanese - Wave height prediction of focused wave packets in shallow water
津田洋輔; 渡部靖憲; 猿渡亜由未, 混相流シンポジウム講演論文集(Web), 2019, ROMBUNNO.B223_0124 (WEB ONLY), 2019
Japanese - 紋別港周辺における冬季海象イベント時の解析手法
早川健; 津田洋輔; 杉村一直; 石見翔汰; 渡部靖憲; 猿渡亜由未, 土木学会北海道支部論文報告集(CD-ROM), 75, ROMBUNNO.B‐07, Jan. 2019
Japanese - 強風イベント時における日本海,太平洋での内部波振動モード
足立天翔; 猿渡亜由未; 宮武誠; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 75, ROMBUNNO.B‐06, Jan. 2019
Japanese - 太平洋北西における爆弾低気圧に伴う高潮の要因別脆弱性評価
福原康平; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 75, ROMBUNNO.B‐04, Jan. 2019
Japanese - Sediment suspension in violent breaking waves
Yasunori Watanabe; Ayumi Saruwatari, 12th European Fluid Mechanics Conference, Sep. 2018
English, Summary national conference - Recent Trends in Wave Climate and Wave Growth by an Explosive Cyclogenesis
猿渡亜由未; 渡部靖憲, 北海道地区自然災害科学資料センター報告, 31, 31‐42, 31 Mar. 2018
Japanese - 大気海面間での運動量交換に与える砕破飛沫と雨滴の影響—INFLUENCE OF SEA SPRAY AND RAINDROP ON THE MOMENTUM EXCHANGE AT AIR-SEA INTERFACE
岡地 寛季; 山田 朋人; 渡部 靖憲, 水工学論文集 Annual journal of Hydraulic Engineering, JSCE / 土木学会水工学委員会 編, 62, Ⅰ_265, 270, 2018
東京 : 土木学会, Japanese - Relation of surface flow and temperature on wind wave faces
Yasunori Watanabe; Kazunao Sugimura; Ayumi Saruwatari, 混相流シンポジウム講演論文集(Web), 2018, WEB ONLY, 2018
Japanese, Summary national conference - Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2016
馬場 康之; 水谷 英朗; 久保 輝広; 内山 雄介; 森 信人; 渡部 靖憲; 山田 朋人; 猿渡 亜由未; 大塚 淳一; 二宮 順一, 京都大学防災研究所年報. B = Disaster Prevention Research Institute Annuals. B, 60, 0, 664, 671, Sep. 2017, [Peer-reviewed]
京都大学防災研究所, Japanese - 爆弾低気圧に伴う広域海面水位移動
福原康平; 本間翔希; 猿渡亜由未; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 73, ROMBUNNO.B‐52, Feb. 2017
Japanese - ディスドロメータを用いた野外飛沫観測
岡地寛季; 山田朋人; 渡部靖憲; 猿渡亜由未; 大塚淳一; 森信人; 馬場康之; 水谷英朗; 久保輝広; 二宮順一; 内山雄介, 土木学会北海道支部論文報告集(CD-ROM), 73, ROMBUNNO.B‐04, Feb. 2017
Japanese - Determination of Sea Spray Droplet Distribution Under Marine Observation and Wind Tunnel Experiment
OKACHI Hiroki; YAMADA Tomohito; Watanabe Yasunori; OOTSUKA Junichi, Proceeding of Annual Conference, 30, 0, 95, 95, 2017, [Peer-reviewed]
海面由来の砕破飛沫に着目した研究では，大気海洋間での運動量・熱交換に与える飛沫の影響が議論されている．現在，海面抵抗は風速が大きくなるにつれて増加するとされている．しかし風速30m/s以上の暴風下では発達した風波と海表面上に分布する砕破飛沫の影響により海面の抵抗が著しく低下-若しくは一定になるという提案がある．砕破飛沫は蒸発することで周りの大気から潜熱を奪う冷却効果を持つ．潜熱を吸収し温度上昇した飛沫が海面に落下することで海面水温を上昇させる．このプロセスにより飛沫が大気海洋間の熱交換に影響を与える．この過程を解明するために飛沫観測する必要があるが，暴風雨下では降雨を伴うため飛沫の物理過程の解明は困難である．一方で雨滴に着目をすると，海洋及び陸での降雨観測は地球全体の水循環を把握するために不可欠である．しかし海洋観測では降雨のみならず砕破飛沫の混合が考えられる．そのため飛沫及び降雨の研究において両者を分類することは不可欠である．本研究では和歌山県田辺湾沖での雨滴及び砕破飛沫の直接観測と砕破飛沫の室内風洞実験を試みた．<br /> 野外観測では雨滴と砕破飛沫の混合したデータから両者を分類し，砕破飛沫の粒径分布を抽出した．また降雨時の粒径分布では風速の増加と共に飛沫の影響と考えられる1mm以下の粒径を持つ粒子数の増加が確認できた．室内実験からは風速が増加するに連れて粒子数の増加，体積の増加，運動量交換に寄与する抵抗係数の減少が確認できた．, THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, Japanese - Survey Report for 2014 Nemuro storm surge
渡部 靖憲; 猿渡 亜由未, 北海道地区自然災害科学資料センター報告 = Bulletin of the Natural Disaster Science Data Center, Hokkaido, 29, 23, 34, Mar. 2016, [Peer-reviewed]
北海道地区自然災害科学資料センター (北海道大学大学院工学研究院), Japanese - 底面に冷熱源を持つ回転水槽実験における回転初期の遷移過程と高さ依存性
一瀬輪子; 北野慈和; 山田朋人; 渡部靖憲; 泉典洋, 土木学会北海道支部論文報告集(CD-ROM), 72, 2016 - Marine observation with disdrometer under strong wind condition
Okachi Hiroki; Yamada Tomohito; Watanabe Yasunori; Saruwatari Alum; Otuka Junichi; Mori Nobuhito; Baba Yasuyuki; Mizutani Hideaki; Kubo Teruhiko; Ninomiya Junnichi; Uchiyama Yuusuke, Proceeding of Annual Conference, 29, 0, 35, 35, 2016
Associated with global warming, the effects of sea level rise are linked to frequency and intensity of storms and other weather events. Previous researches argue that sea spray affects the development of typhoons. This study reports a marine observation on Tanabe bay near Wakayama Prefecture utilizing a measurement instrument called parsivel. Parsivel can detect the diameter of a droplet and the distribution of velocity. In our observation point, we reveal the presence of spray droplets with 1.5mm ~ 5.510mm diameter when typhoon events occurs in 2015. We discuss the relationship between sea spray and wind velocity when storm events occurs.<br>, 水文・水資源学会, Japanese - Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2016
馬場 康之; 水谷 英朗; 久保 輝広; 内山 雄介; 森 信人; 渡部 靖憲; 山田 朋人; 猿渡 亜由未; 大塚 淳一; 二宮 順一, 京都大学防災研究所年報, 60, 664, 671, 2016, [Peer-reviewed]
京都大学防災研究所, Japanese - 0327 Evolution of free-surfaces in breaking waves
WATANABE Yasunori, Fluids engineering conference ..., 2015, "0327, 1"-"0327-2", 07 Nov. 2015
When a wave-breaking jet plunges onto the forward wave trough, three-dimensional organized free-surface flows with longitudinal counter-rotating vortices are organized at the plunging location. The finger jets are induced through free-surface entrainment by the vortices beneath the surface. The surface tension destabilize the jets to form multiple droplets. Fundamental features of the series of free-surface deformation during the wave breaking process are studied on the basis of numerical computations and laboratory experiments., The Japan Society of Mechanical Engineers, Japanese - ディスドロメータを用いた飛沫粒径分布の風速及び高度依存性
岡地寛季; 山田朋人; 渡部靖憲; 猿渡亜由未; 大塚淳一; 馬場康之; 水谷英朗; 久保輝広; 二宮順一; 内山雄介; 森信人, 地球環境シンポジウム講演集, 23rd, 149, 150, 02 Sep. 2015
Japanese - 海氷群を伴う津波の陸上遡上による被害想定の研究概要(海氷の衝突破壊・挙動および陸上遡上の実験/数値シミュレーションの試み)
KIOKA SHINJI; TAKEUCHI TAKAHIRO; WATANABE YASUNORI, 混相流, 29, 2, 124, 131, 15 Jun. 2015
East coasts of Hokkaido, facing Okhotsk Sea and Pacific Ocean, are covered by sea ice drifted from northern Okhotsk Sea in late January through early of March. When tsunami occurs during the term and arrives at the ice-covered coasts, the disaster risks are significantly increased since ice floes carried by run-up tsunami can extend the possible damages through distinct dynamic behaviors occurring in ice-floe-laden flows; that is, forming pile-ups and jams of the ice floes, and enhancing ice and hydraulic forces. In this paper, features of the previous damages to residences and infrastructures by sea ice for the 1952 Tokachi-oki tsunami and the 2011 Tohoku tsunami are firstly discussed for charactering the ice-structure interactions. The fracture mechanisms of the ice floes colliding to structures during jamming and piling-up processes are identified on the basis of model experiments as well as numerical computations using a 3D Distinct Element Method. We also find structures with openings, such as windows and space between columns, induce ice jams and pile-ups and dam up the run-up flows, resulting in downstream water level rise and thus significant increase of hydraulic pressure acting on the structure, which indicates the increased risks expected in urban area., THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, Japanese - 底面の加熱および冷却を伴う回転流体水槽実験
一瀬輪子; 山田朋人; 北野慈和; 渡部靖憲; 泉典洋, 土木学会北海道支部論文報告集(CD-ROM), 71, 2015 - P236 底面からの加熱及び冷却を伴う回転水槽実験(ポスターセッション)
北野 慈和; 一瀬 輪子; 山田 朋人; 渡部 靖憲; 泉 典洋, 大会講演予講集, 107, 267, 267, 2015, [Peer-reviewed]
日本気象学会, Japanese - Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2015
馬場 康之; 水谷 英朗; 久保 輝広; 内山 雄介; 森 信人; 渡部 靖憲; 山田 朋人; 猿渡 亜由未; 大塚 淳一; 二宮 順一, 京都大学防災研究所年報, 59, 431, 437, 2015, [Peer-reviewed]
This paper shows some results of a field observation carried out in the summer of 2015. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. In the summer in 2015, no typhoon approached around the observation site, and the high wave and strong wind conditions have not been captured during the observation. Several short-term rainfalls due to front and low pressure occurred, and it is reported that local areas in Shirahama town and neighboring towns suffered some damages with windblasts from late August to early September. It is found in the observation results of water temperature that the temporal variations of water temperature have a period of 3 to 6 days in the deeper layers like 20m deep and 30m deep. The cyclical fluctuation of water temperature at 30m deep has opposite phase to the fluctuation of salinity. This result means that low temperature and high salinity water approaches to the observation site periodically and that some influences of the water mass of the open sea exist., 京都大学防災研究所, Japanese - 強風下に伴う混合気液界面の熱画像計測
TASHIRO KOKI; WATANABE YASUNORI; YAMADA TOMOHITO; OTSUKA JUN'ICHI; OYAMA TAKAHIRO, 土木学会北海道支部論文報告集(CD-ROM), 70, ROMBUNNO.B-65, Feb. 2014
Japanese - 風洞水槽における有義波高の影響を考慮した鉛直風速分布に関する考察
OYAMA TAKAHIRO; YAMADA TOMOHITO; WATANABE YASUNORI; OTSUKA JUN'ICHI, 土木学会北海道支部論文報告集(CD-ROM), 70, ROMBUNNO.B-64, Feb. 2014
Japanese - 内部ケルビン波の砕波により誘起される水平循環
小窪一毅; 中山恵介; 新谷哲也; 柿沼太郎; 大塚淳一; 渡部靖憲; 駒井克昭; 清水健司, 土木学会北海道支部論文報告集(CD-ROM), 70, 2014 - Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2014
馬場 康之; 水谷 英朗; 久保 輝広; 内山 雄介; 森 信人; 渡部 靖憲; 山田 朋人; 猿渡 亜由未; 大塚 淳一; 二宮 順一, 京都大学防災研究所年報, 58, 315, 320, 2014, [Peer-reviewed]
This paper shows some results of a field observation carried out in the summer of 2014. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity and dissolved oxygen level observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. In the summer in 2014, a total of 4 typhoons (No.11, No.12, No.18 and No.19) approached to the Kii peninsula, and the high wave and strong wind conditons due to 2 typhoons (No.18 and No.19) have been captured during the observation. When the typhoons passed around the observation site, the high wave and strong wind occurred. However, the observation data of 2014 doesn't have clear shift of water temperature and salinity like the one by the typhoon No.18 in 2013. On the other hand, it is repeatedly found in the observed data that the reduction of water temperature and the increase of salinity happened simultaneously. This result indicates that the water temperature and the salinity around the observation site have some influence of the water mass of the open sea., 京都大学防災研究所, Japanese - Computational wave dynamics
Hitoshi Gotoh; Akio Okayasu; Yasunori Watanabe, Computational Wave Dynamics, 1, 234, 01 Jan. 2013
Others - Preface
Hitoshi Gotoh; Akio Okayasu; Yasunori Watanabe, Computational Wave Dynamics, v, vii, 01 Jan. 2013
Others - Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2013
馬場 康之; 水谷 英朗; 久保 輝広; 内山 雄介; 森 信人; 渡部 靖憲; 山田 朋人; 猿渡 亜由未; 大塚 淳一, 京都大学防災研究所年報, 57, 455, 461, 2013, [Peer-reviewed]
This paper shows some results of a field observation carried out in the summer of 2013. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity and dissolved oxygen level observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. During the observation, one typhoon (No.18, MAN-YI) approached to the Kii peninsula. When the typhoon passed around the observation site, the vertical mixing develops well, and water temperature at all measurement points show almost uniform distributions. It is also found during the typhoon passing that coastal upwelling through the Ekman transport happened clearly due to continuous southward wind. An EOF analysis decomposes the water temperature variation during the typhoon passing into 1) the increase and decease of water temperature and 2) the magnitude of the temperature difference in the vertical direction., 京都大学防災研究所, Japanese - Behaviors of the 2011 Tohoku Earthquake Tsunami on the Pacific Coast of Hokkaido
渡部 靖憲, 北海道地区自然災害科学資料センター報告, 25, 0, 3, 22, Mar. 2012, [Peer-reviewed]
北海道大学大学院工学研究科北海道地区自然災害科学資料センター, Japanese - 異なる成層場における内部ケルビン波の斜面上での砕波
小窪一毅; 中山恵介; 新谷哲也; 丸谷靖幸; 岡田知也; 渡部靖憲, 土木学会北海道支部論文報告集(CD-ROM), 68, 2012 - 内部ケルビン波の砕波により発生する流れに関する研究
小窪一毅; 中山恵介; 新谷哲也; 大塚淳一; 岡田知也; 渡部靖憲; 丸谷靖幸, 土木学会年次学術講演会報告集, 67, II-055, 2012
Japanese, Summary national conference - Bioluminescence Imaging Measurements of Fluid Stresses
渡部 靖憲, 可視化情報学会誌, 31, 1, 19, 22, 2011, [Peer-reviewed]
可視化情報学会, Japanese - 強風下における微細飛沫生成・輸送過程の数値計算法の開発
阿部伸弘; 猿渡亜由未; 渡部靖憲, 論文報告集, 土木学会北海道支部, 66, B-46, 2010
Japanese - 3DPTV for a large domain and its application to large-scale turbulence
Watanabe Yasunori, Journal of the Visualization Society of Japan, 22, 1, 383, 384, 2002, [Peer-reviewed]
Lagrangian fluid motion under breaking waves and settling motion of glass-particles released into a still water are measured by the 3D stereoscopic particle tracking velocimetry for a large domain (3DSPTV-LD). Since the 3DSPTV-LD dose not require to use a laser sheet for illuminating a single flow plane in a measur domain, it has an advantageous feature in engineering use -i.e. high applicability to 3D measurementsfor a large domain on less costs. In coastal engineering, the large-scale turbulence associated with a large-scale eddy structur, such as a separated vortex array around a structure, which futures three-dimensional behav-iora.is one of the crucial factors affecting sediment transport and stability of a structurc.The 3DSPTV-LD enables it to acquire the 3D large-scale Lagrangian motion over a wide area., The Visualization Society of Japan, Japanese - 波動場におけるブロック潜堤間隙内の三次元流体運動に関する実験的研究
重松 孝昌; 渡部 靖憲; 竹原 幸生; 奥村 悠樹; 小池 敏也, 海岸工学論文集, 49, 49, 806, 810, 2002, [Peer-reviewed]
従来, 測定が困難であった多孔質構造物間隙内の三次元流体運動を計測するシステムの構築を行っている. 構造物と流体の屈折率を調整することにより, 物体背後の構造物および流体を視認することができ, さらに, 拡張型三次元ステレオグラムPTV流速計測システムを用いることにより, 間隙内流体運動の計測が可能になっている. 新たに中立粒子の開発も行っている. 構築したシステムを用いて, 波動場におけるテトラポッド潜堤の間隙流体運動の計測を行い, 三次元流速分布および乱れエネルギーの空間分布について考察している., 公益社団法人 土木学会, Japanese
- Dynamics of water surface flows and waves
Watanabe, Yasunori
CRC Press, 2022, 9780367690427, xv, 279 p., English - Computational Wave Dynamics (Advanced Series on Ocean Engineering)
Hitoshi Gotoh; Akio Okayasu; Yasunori Watanabe
World Scientific Publishing Company, 04 Jun. 2013, 9814449709, 234
- Asian and Pacific Coasts 2003 (with CD-ROM) : Proceedings of the 2nd International Conference, Makuhari, Japan 29 February - 4 March 2004
Yoshimi Goda; Wataru Kioka; Kazuo Nadaoka
World Scientific Pub Co Inc, Apr. 2004, 9812385584, 304
- Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2016
馬場康之; 水谷英朗; 久保輝広; 内山雄介; 森信人; 渡部靖憲; 山田朋人; 猿渡亜由未; 大塚淳一; 二宮順一
京都大学防災研究所年報(CD-ROM), Sep. 2017, Japanese - ディスドロメータを用いた野外飛沫観測
岡地寛季; 山田朋人; 渡部靖憲; 猿渡亜由未; 大塚淳一; 森信人; 馬場康之; 水谷英朗; 久保輝広; 二宮順一; 内山雄介
土木学会北海道支部論文報告集(CD-ROM), Feb. 2017, Japanese - Determination of Sea Spray Droplet Distribution Under Marine Observation and Wind Tunnel Experiment
OKACHI Hiroki; YAMADA Tomohito; Watanabe Yasunori; OOTSUKA Junichi
Proceeding of Annual Conference, 2017, Japanese
海面由来の砕破飛沫に着目した研究では，大気海洋間での運動量・熱交換に与える飛沫の影響が議論されている．現在，海面抵抗は風速が大きくなるにつれて増加するとされている．しかし風速30m/s以上の暴風下では発達した風波と海表面上に分布する砕破飛沫の影響により海面の抵抗が著しく低下-若しくは一定になるという提案がある．砕破飛沫は蒸発することで周りの大気から潜熱を奪う冷却効果を持つ．潜熱を吸収し温度上昇した飛沫が海面に落下することで海面水温を上昇させる．このプロセスにより飛沫が大気海洋間の熱交換に影響を与える．この過程を解明するために飛沫観測する必要があるが，暴風雨下では降雨を伴うため飛沫の物理過程の解明は困難である．一方で雨滴に着目をすると，海洋及び陸での降雨観測は地球全体の水循環を把握するために不可欠である．しかし海洋観測では降雨のみならず砕破飛沫の混合が考えられる．そのため飛沫及び降雨の研究において両者を分類することは不可欠である．本研究では和歌山県田辺湾沖での雨滴及び砕破飛沫の直接観測と砕破飛沫の室内風洞実験を試みた．
野外観測では雨滴と砕破飛沫の混合したデータから両者を分類し，砕破飛沫の粒径分布を抽出した．また降雨時の粒径分布では風速の増加と共に飛沫の影響と考えられる1mm以下の粒径を持つ粒子数の増加が確認できた．室内実験からは風速が増加するに連れて粒子数の増加，体積の増加，運動量交換に寄与する抵抗係数の減少が確認できた． - Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2015
馬場康之; 水谷英朗; 久保輝広; 内山雄介; 森信人; 渡部靖憲; 山田朋人; 猿渡亜由未; 大塚淳一; 二宮順一
京都大学防災研究所年報(CD-ROM), Sep. 2016, Japanese - 海上観測と風洞水槽実験による強風下における飛沫の総量及び粒径分布
岡地寛季; 山田朋人; 渡部靖憲; 大塚淳一; 長尾賢汰
土木学会北海道支部論文報告集(CD-ROM), Jan. 2016, Japanese - Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2016
馬場 康之; 水谷 英朗; 久保 輝広; 内山 雄介; 森 信人; 渡部 靖憲; 山田 朋人; 猿渡 亜由未; 大塚 淳一; 二宮 順一
京都大学防災研究所年報, 2016, Japanese - 底面からの加熱及び冷却を伴う回転水槽実験
KITANO YOSHIKAZU; ICHINOSE RINKO; YAMADA TOMOHITO; WATANABE YASUNORI; IZUMI NORIHIRO
日本気象学会大会講演予稿集, 30 Apr. 2015, Japanese - 強風下における高速表面水温計測を用いた風波の熱輸送変調の解析
WATANABE YASUNORI; TASHIRO KOKI; OTSUKA JUN'ICHI; OYAMA TAKAHIRO; YAMADA TOMOHITO
土木学会北海道支部論文報告集(CD-ROM), Jan. 2015, Japanese - Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2015
馬場 康之; 水谷 英朗; 久保 輝広; 内山 雄介; 森 信人; 渡部 靖憲; 山田 朋人; 猿渡 亜由未; 大塚 淳一; 二宮 順一
京都大学防災研究所年報, 2015, Japanese
This paper shows some results of a field observation carried out in the summer of 2015. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. In the summer in 2015, no typhoon approached around the observation site, and the high wave and strong wind conditions have not been captured during the observation. Several short-term rainfalls due to front and low pressure occurred, and it is reported that local areas in Shirahama town and neighboring towns suffered some damages with windblasts from late August to early September. It is found in the observation results of water temperature that the temporal variations of water temperature have a period of 3 to 6 days in the deeper layers like 20m deep and 30m deep. The cyclical fluctuation of water temperature at 30m deep has opposite phase to the fluctuation of salinity. This result means that low temperature and high salinity water approaches to the observation site periodically and that some influences of the water mass of the open sea exist. - LIFを用いた巻き波ジェット波浪場に関する可視化実験
SUZUKI TAKURO; WATANABE YASUNORI
土木学会北海道支部論文報告集(CD-ROM), Jan. 2015, Japanese - マイクロバブル墳流の流体力学的特性
OYAIZU HARUHI; WATANABE YASUNORI; SATO HISASHI
土木学会北海道支部論文報告集(CD-ROM), Jan. 2015, Japanese - 暴風雨下における液滴効果を加味した海面粗度パラメタリゼーション
OYAMA TAKAHIRO; YAMADA TOMOHITO; WATANABE YASUNORI; SARUWATARI AYUMI; OTSUKA JUN'ICHI; TASHIRO KOKI
土木学会北海道支部論文報告集(CD-ROM), Jan. 2015, Japanese - 沿岸域住民を対象とした津波災害に対する防災意識とその変遷
MIYAMURA AYUMI; TANAKA GAKU; WATANABE YASUNORI
土木学会北海道支部論文報告集(CD-ROM), Jan. 2015, Japanese - Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2013
BABA YASUYUKI; MIZUTANI HIDEAKI; KUBO TERUHIRO; UCHIYAMA YUSUKE; MORI NOBUHITO; WATANABE YASUNORI; YAMADA TOMOHITO; SARUWATARI AYUMI; OTSUKA JUN'ICHI
京都大学防災研究所年報(CD-ROM), Sep. 2014, Japanese - 内部ケルビン波の砕波により誘起される水平循環
小窪一毅; 中山恵介; 新谷哲也; 柿沼太郎; 大塚淳一; 渡部靖憲; 駒井克昭; 清水健司
土木学会北海道支部論文報告集(CD-ROM), Feb. 2014, Japanese - Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2014
馬場 康之; 水谷 英朗; 久保 輝広; 内山 雄介; 森 信人; 渡部 靖憲; 山田 朋人; 猿渡 亜由未; 大塚 淳一; 二宮 順一
京都大学防災研究所年報, 2014, Japanese
This paper shows some results of a field observation carried out in the summer of 2014. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity and dissolved oxygen level observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. In the summer in 2014, a total of 4 typhoons (No.11, No.12, No.18 and No.19) approached to the Kii peninsula, and the high wave and strong wind conditons due to 2 typhoons (No.18 and No.19) have been captured during the observation. When the typhoons passed around the observation site, the high wave and strong wind occurred. However, the observation data of 2014 doesn't have clear shift of water temperature and salinity like the one by the typhoon No.18 in 2013. On the other hand, it is repeatedly found in the observed data that the reduction of water temperature and the increase of salinity happened simultaneously. This result indicates that the water temperature and the salinity around the observation site have some influence of the water mass of the open sea. - Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2013
馬場 康之; 水谷 英朗; 久保 輝広; 内山 雄介; 森 信人; 渡部 靖憲; 山田 朋人; 猿渡 亜由未; 大塚 淳一
京都大学防災研究所年報, 2013, Japanese
This paper shows some results of a field observation carried out in the summer of 2013. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity and dissolved oxygen level observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. During the observation, one typhoon (No.18, MAN-YI) approached to the Kii peninsula. When the typhoon passed around the observation site, the vertical mixing develops well, and water temperature at all measurement points show almost uniform distributions. It is also found during the typhoon passing that coastal upwelling through the Ekman transport happened clearly due to continuous southward wind. An EOF analysis decomposes the water temperature variation during the typhoon passing into 1) the increase and decease of water temperature and 2) the magnitude of the temperature difference in the vertical direction. - 内部ケルビン波の砕波により発生する流れに関する研究
小窪一毅; 中山恵介; 新谷哲也; 大塚淳一; 岡田知也; 渡部靖憲; 丸谷靖幸
土木学会年次学術講演会講演概要集(CD-ROM), 01 Aug. 2012, Japanese - Behaviors of the 2011 Tohoku Earthquake Tsunami on the Pacific Coast of Hokkaido
WATANABE YASUNORI
北海道地区自然災害科学資料センター報告, 31 Mar. 2012, Japanese - 異なる成層場における内部ケルビン波の斜面上での砕波
小窪一毅; 中山恵介; 新谷哲也; 丸谷靖幸; 岡田知也; 渡部靖憲
土木学会北海道支部論文報告集(CD-ROM), Feb. 2012, Japanese - Bioluminescence Imaging Measurements of Fluid Stresses
WATANABE YASUNORI
可視化情報学会誌, 01 Jul. 2011, Japanese - On The Wave Boundary Layer Over The Rippled Bed.
WATANABE YASUNORI
都市域急流河川の流れと河床変動の数値解析に関するシンポジウム 平成6年, 1994, Japanese
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- Coastal disasters induced by violent breaking waves
Grants-in-Aid for Scientific Research
01 Apr. 2023 - 31 Mar. 2028
渡部 靖憲; 猿渡 亜由未; 新井田 靖郎; 二宮 順一; 馬場 康之; 大塚 淳一; 志村 智也; 内山 雄介; 森 信人
タスク1：暴風下における沿岸砕波過程を通した大気―海洋相互作用：（1-1）高速風洞実験：最大風速35m/sを超える強風場での波浪実験が可能な既存の大型風洞水槽底部から照明を照射できるよう底部に透明ガラスを設置し，Diffusive Light Photographyによって水面の面的形状を計測する準備を行った．これによりレーザー干渉技術と同期させ，放出飛沫のサイズ分布と飛沫速度に加え，飛沫放出のソースとなる波面のスピュームの発生を同定可能となる．
タスク2：砕波組織渦による海底，前浜，壁面での底質浮遊と飛沫放出：（2-1）造波実験：前浜の波浪の遡上過程，面的水面変動をLaser Induced Fluorescence法により計測する基礎技術を開発した．また，波面下の３次元流速分布を高解像度で計測するため，Super-resolution PIVを開発し，精度検証を行った．（2-2）数値実験：砕波帯，前浜で顕著となる多分散性浮遊砂群の３次元的組織渦構造への影響をモデル化するため，新たにモーメント法を導入し，沈降粒子群の粒度分布の特徴を調査した．任意形状の防波堤及び消波ブロックとの波浪との相互作用の解析を可能とするGhost cell法を既存の砕波乱流モデルに導入し，消波ブロックの間隙内部で発達する乱流を再現可能となった．
タスク3：異常海象時の災害評価：（3-1）海象観測：和歌山県白浜町田辺中島高潮観測塔および北海道氷海展望塔オホーツクタワーにおいて，台風および爆弾低気圧の来襲に対する海洋応答を観測した．新たな白波波峰長抽出技術の開発により波浪エネルギー散逸の時間変化を見積もると同時に，３次元スペクトル解析によって白波の時空間スケールの取得が可能となった．
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 23H00191 - Estimation of probability and maximum potential intensity of extreme coastal hazards using global and regional integrated models
Grants-in-Aid for Scientific Research
01 Apr. 2023 - 31 Mar. 2027
森 信人; 馬場 康之; 渡部 靖憲; 竹見 哲也; 二宮 順一; 志村 智也; 宮下 卓也; 豊田 将也; 福井 信気; 今井 優樹
本年度は以下の3項目について，計画に沿った成果を得た．
項目A 「台風の現地観測」大気海洋境界面における運動量・熱交換のパラメタリゼーション定量化のために詳細な運動量・熱交換過程の観測，漂流ブイによる台風目近傍の観測，最新の衛星データ収集・解析を実施した．項目Bで定量化する大気海洋境界面のパラメタリゼーションのため，高風速をターゲットに大気・海洋観測塔（京都大学海洋観測塔）を用いた集中観測を実施した．既存の設備を最大限生かし，通過する台風の気温・水温，風速，長波短波放射等の大気・海洋間の高精度計測を実施し，運動量・熱フラックス等の詳細データを得た．風付近の波浪，海面水温等の測定が可能な漂流ブイを多数投入し，30m/s以上の高風速のデータの収集を実施した．
項目B 「全球と領域の大気・海洋・高潮・波浪統合モデル開発」
本年度は，運動量・熱交換のパラメタリゼーションの理論再構築を実施した．波浪境界層理論をもとに風速と波浪の方向スペクトルを説明変数として考え，交換量のバルク式について理論的な枠組みを再構築について着手した．
項目C 「極端沿岸ハザード評価」月平均の気候値から台風・高潮・高波の可能最大値を推定する可能最大ハザードモデルを開発した．
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Kyoto University, 23H00196 - Experimental proof of coastal rogue waves
Grants-in-Aid for Scientific Research Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))
07 Oct. 2022 - 31 Mar. 2026
渡部 靖憲
タスク１ 水深変化，流れを伴う沿岸域における空間集中巨大波
申請者が開発した流れ中の波浪集中理論を数値的造波信号に変換するアルゴリズムを開発した．これをもって，エジンバラ大学所有の大型実験施設FloWaveにおいて，沿岸域で波浪伝播の特徴である水深変化及び流れによる浅水変形を伴う分散性波群の空間集中を発生させ，アルゴリズムの妥当性を検証した．国内研究者５名全員及び海外研究者２名によってFloWaveにおいて実証実験を行った．はじめに，発生させる流れの水平流速の鉛直分布を水槽全面に渡ってAcoustic Doppler Velocimeterによって計測し，流れパラメータを確定させた．流れなしでの巨大波生成は理論と矛盾なく成功し，大規模波浪集中を実証した一方，高速流れ中では集中距離及び時間が変動し，さらなる検討が必要であることが判明した．各地点における水位変動分布及び撮影画像を国内の研究機関に持ち込み，分析を行い，周波数，波数遷移と増幅率の関係を調査した．高速流れにおける集中位置の理論との差異が，造波信号作成プログラムにおけるバグであることを明らかにし，修正を行った．
タスク２ 交差波間の非線形エネルギー輸送を経た非線形集中巨大波
多方向からの集中波群を１点の集中地点において巨大波を生成する理論を，波数の経路積分に対するフェルマーの原理から解析し，多項式近似を行って時間変動する初期造波角度を与えるアルゴリズムを開発し，数値実験からその妥当性を検証した．この理論に基づいた造波信号生成プログラムを作成した．
Japan Society for the Promotion of Science, Fund for the Promotion of Joint International Research (Fostering Joint International Research (B)), Hokkaido University, 22KK0057 - Heat and moisture transfer in the unsaturated wave field under explosive cyclones
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
01 Apr. 2022 - 31 Mar. 2025
猿渡 亜由未; 渡部 靖憲
本研究では冬季爆弾低気圧の通過経路頻度の高い北海道オホーツク海沿岸の紋別市オホーツクタワーにおける気象海象連続観測に基づく大気海洋間輸送フラックスの海面状態への依存性を明らかにすることを目指して研究を継続している．
2023年度は海面画像を取得するために2022年度に新たに設置した2台のウェブカメラの撮影条件並びにキャリブレーション方法の改善を行った．更に1組の画像ペア間での画像相関点の計算法に大幅な修正を加えることにより，2022年度は概形の推定にとどまっていた暴波浪時の白波波面の３次元形状をより詳細に取得することに成功した．２つの画像から求められた個別の波の三次元波面形状（波高，波速）は，オホーツクタワーから18 km東に位置する全国港湾海洋波浪情報網（ナウファス）の紋別（南）観測点における統計波浪観測データと矛盾しない結果となっており，本研究で開発したカメラ画像を元にした三次元白波波面形状測定法の有用性を示すことができた．2023年度は共同研究者が主導する他の研究プロジェクトにおいて，オホーツクタワーの水面下に新たな水中観測器として波高計並びに水温計の設置を行い，これらにより取得されたデータを本研究のためにも用いることで同意を得ている．これまで観測結果の解析には紋別（南）ナウファスデータの浅水変形を考慮した換算値から波高データを用いていたが，同一地点での大気海洋データ同士の直接比較が可能となる．また，オホーツクタワーでは当研究の研究協力者が新たに船舶用データを設置する準備を進めており，これもまた得られたデータを本研究のために用いていいとの合意を得ている．これが稼働し始めればタワー地点での波浪データだけではなく，その周辺海域における波浪情報も取得することができるため，荒天時の暴波浪の発達伝搬に関するデータの充実が図られる．
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 22K04324 - 巨礫分布特性にもとづく１万年スケールのスーパー台風評価についての国際共同研究
科学研究費助成事業 国際共同研究加速基金(国際共同研究強化(B))
27 Oct. 2020 - 31 Mar. 2025
森 信人; 渡部 靖憲; 安田 誠宏; 中條 壮大; 下園 武範; 二宮 順一; 志村 智也; 宮下 卓也; 張 哲維
本研究では，過去数百～数千年間に海中から移動し，陸域に打ち上げられた巨礫の移動限界とその分布について，北西太平洋を対象に国際共同調査・モデル開発を実施する．このため，近年および記録のない過去イベントで発生した巨礫の大きさ，物性，年代および沿岸地形について計測し，巨礫群の詳細な特性を把握する．第2に，巨礫の分布特性を説明可能な巨礫移動モデルを国際共同開発する．第3に，近年移動した巨礫の調査結果を元に，外力である沿岸域の暴波浪およびスーパー台風特性を逆推定する手法を開発し，最後に確率台風モデル等を組合せ，過去巨礫群を説明可能な1万年単位の最大級の暴波浪とスーパー台風の強度についての逆推定を実施する．
本年度は，近年の極端イベントにより移動が確認されている近代巨礫群の位置，3D形状，物性，陸上および海底地形の計測のための観測機器の整備およびその計測精度の確認を実施した．これと並行して，数値モデル開発を進め，質点移動として台風石の移動をリーフ上の流体力推定から生成，回転・並行移動を計算する数値巨礫移動モデルを開発した．
海外の共同研究では，Frediric Dias・ダブリン大学・教授およびAndrew Kennedy・ノートルダム大学・教授と巨礫発生・移動モデルの開発を進めた．Wen-Son Chiang・国立成功大学台南水理研究所・副所長とは，次年度以降の観測についての意見交換を行った．
日本学術振興会, 国際共同研究加速基金(国際共同研究強化(B)), 京都大学, 20KK0095 - Interaction of atmospheric-ocean boundary processes considering ocean waves and their impact on coastal hazards
Grants-in-Aid for Scientific Research
01 Apr. 2019 - 31 Mar. 2023
Mori Nobuhito
The effects of ocean surface waves as a sea surface boundary process on sea surface wind speed, storm surge, typhoons and the climate system are not adequately addressed physically in many integrated numerical models. In this study, we conducted field observations of the atmosphere-ocean boundary process. Based on the observation results, we re-parameterized the sea surface processes considering waves. Based on the results, we applied the obtained results to numerical models of extreme events such as storm surge, storm surge, and typhoons, as well as global atmosphere and ocean models, and evaluated their impacts. In addition, quantitative estimates of the extreme typhoons, storm surges, and storm waves are made, and the impact of sea-surface processes on the climate system is clarified using a global climate model.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Kyoto University, 19H00782 - Formation and prediction of coastal rogue waves
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory)
28 Jun. 2019 - 31 Mar. 2022
Yasunori Watanabe
A nonlinear wave model to estimate wave growth and maximum crest height of focussing wave groups was developed and validated with the experimental results. The shallow water wave focusing theory has been also extended to the one with wave-curent interactions. We found that the presence of opposing current significantly amplifies the focusing waves upto six times of the initial wave height, which depends on a wave spectrum of the initial wave group. We also performed physical and computational experiments to simulate planar focusing wave groups, and found that possible effects of nonlinear energy transfers among crossing waves and flip-through phenomenon caused by the crossing wave impacts to further growth of focussing waves expected in a coastal region.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Hokkaido University, 19K21981 - The mechanisms of submarine slope failures due to earthquakes and the resulting turbidity currents
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
01 Apr. 2019 - 31 Mar. 2022
IZUMI Norihiro
We investigated the physical processes of submarine landslides triggered by earthquakes and the resulting tsunami and turbidity currents from the viewpoints of laboratory experiments, theoretical analysis, and numerical simulations.
We studied the movement of turbidity currents by solving the layer-averaged momentum equations, continuity equation, and the transport equation of suspended sediment of turbidity currents numerically. The results show that the transition from a landslide to a turbidity current that can travel long distances does not depend on the initial suspended sediment concentration or velocity unless the initial Richardson number is greater than unity.
We developed numerical simulation models to reproduce tsunamis caused by a submarine landslide and those generated by the superposition of tsunamis generated by a submarine landslide and an active fault.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 19H02242 - Mechanical interactions between High-speed marine boundary layer flows and ocean waves
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
01 Apr. 2018 - 31 Mar. 2022
Yasunori Watanabe
We developed computational models to simulate turbulence transitions over waves, formations of thermal boundary layers, and bubble-mediated turbulent flows, which provides physical mechanims contributing to sea-surface drag forces and momentum transfers between atmosphere and ocean. In wind tunnel experiemnts, for the first, we succesfully measured size spectra of the both of sea spray dispersed in atmosphere and air bubbles entrained into sea owing to wind wave breaking, which is related to the sea surface drag and bulk parameters. Contributions of gas dissolution from the entrained bubbles to air-sea gas exchages have been identified through physical and computational experiments. A new model of bubble drag in bubble clouds was also developed in this project, contributing physical understanding of wave-induced aeration process. In ocean observation, features of sea spray, bubble entrainment due to wind wave breaking, and their contributions to heat transfers across sea surfaces.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 18H03791 - Estimation of Historical Typhoons from the Distribution of Large Coastal Boulders in Subtropical Coastal Areas
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory)
29 Jun. 2018 - 31 Mar. 2021
Mori Nobuhito
In recent years, there are many researches on the distribution of large coastal boulders that have moved from the sea and run-up on land. We attempted to estimate the wave forces and related typhoon intensity from the observed distribution of typhoon boulders. In order to estimate the boulder movement by numerical models, we conducted hydraulic model experiments of boulder movement for solitary waves simulating tsunami and irregular waves simulating typhoon waves. In the case of solitary waves, the distance traveled by boulders was larger when the horizontal bed was dried out, and in the case of irregular waves, when the bed was submerged. In addition, a numerical model of the boulder movement phenomenon was developed, and its range of application and model optimization were carried out using the results of hydraulic experiments. Good results were obtained for the distance of boulder movement by solitary wave and irregular wave.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Kyoto University, 18K18878 - Concentration of organic matter in municipal wastewater by membrane processes with extremely intensive membrane cleaning: sewage systems can be transformed into energy generating infrastructures
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Pioneering)
29 Jun. 2018 - 31 Mar. 2021
Kimura Katsuki
Organic matter in municipal wastewater can be recovered and concentrated by using direct membrane filtration (DMF) adequately, which leads to net-generation of energy from wastewater. Flat-sheet ceramic membranes are physically and chemically robust, and therefore intensive membrane cleanings that cannot be used with polymeric membranes can be used. In this study, DMF of municipal wastewater by flat-sheet ceramic membranes was investigated. With the aid of intensive physical and chemical cleaning, long-term operations under high membrane fluxes were possible. In addition, switching the feed from of the influent of the primary sedimentation basin to the effluent, very short-period aeration, alternative use of acid and oxidant in chemically enhanced backwash were found to be effective for mitigation of membrane fouling in DMF.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Pioneering), Hokkaido University, 20K20351 - Creation of natural-force-adaptive rivers based on the physical mechanism of long-term meandering evolution
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
01 Apr. 2015 - 31 Mar. 2020
Shimizu Yasuyuki
This study systematizes a wide range of knowledge about the long-term dynamics of meandering, and builds the basic technology for realizing river development that makes full use of natural power and individuality. In particular, focusing on the meandering that determines the plane alignment of river topography, we deeply consider the fundamental mechanism of both short-term fluctuations due to sudden disasters and long-term topographical changes from past to future, and clarified the phenomena. In addition, we analyzed the various impacts on meandering, such as vegetation, presence of estuaries and river structures, diversity of meteorological and topographical geological conditions by theoretical analysis, field surveys, and simplified physical experiments. We also have constructed a computational model that can predict the meandering development transition considering various hydraulic conditions.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 15H02267 - Field survey of coastal mega boulders induced by typhoons and tsunamis in the low to mid-latitude
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
01 Apr. 2015 - 31 Mar. 2018
Mori Nobuhito; KENNEDY Andrew
A earthquake tsunami occurs is along the plate boundary but they are co-exists tropical cyclone active regions in the tropical to mid-latitudes. In the case of Okinawa, clear overlapping of tsunami and typhoon induced boulders, and therefore understanding coastal boulder characteristics by tsunamis and tropical cyclone waves is important to know.
In this study, the distribution of coastal boulders transported from the ocean to land were survey in the Pacific Rim and the Caribbean Ocean. It can evaluate the historic gigantic tsunami and typhoons, potentially. The main objective is to conduct extensive and detailed field investigations on the size, position, physical properties and coastal topography of tropical coast. Based on the results of survey, the distributions and characteristics of boulders in the Pacific Rim and the Caribbean Sea will be summarized for the estimation of magnitude historical of events of tsunami and tropical cyclones.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Kyoto University, 15H05220 - Modifications of drag force and heat transfer across air-water mixing surface layers developed in a violent wave state
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
2015 - 2018
Yasunori Watanabe
We found fundamental features of heat and gas transport in aerated ocean surface layers and modifications of surface drag in violent wave field through experimental parameterization of effects of sea sprays and bubbles entrained by wind wave breaking, computational identifications of heat and gas transfer owing to surface replacement under breaking waves, variable features of surface drag depending on transitions of three-dimensional vortex structures over ocean waves. As sea sprays dispersed in wind boundary layers disrupt the organization of the vortices formed over the breaking waves, causing transitions to fully developed turbulent boundary layer and modifications of surface drag. This process also changes the total momentum and heat fluxes between atmosphere and ocean.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, Competitive research funding, 15H04043 - Development of river planning tools considering large-scale spatial and temporal non-linear characteristics in flood risks
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
01 Apr. 2013 - 31 Mar. 2017
Kimura Ichiro
To enable a large-scale river planning considered connections of whole river basin, we developed novel numerical and mathematical tools, and checked their validity by applying them to flood events with different temporal and spatial scales. The tools are composed of flood physics model, flood economic model and flood evacuation model. The flood physics model is the most fundamental part for the river planning, and is divided into 4 components, the large-scale inundation model, inner-outer inundation connected model, flood induced local flow model and tsunami model. Those tools were tested through the applications to past flood events with different scales, and the results were compared with observations. Such calibration process showed that the river planning aided by the proposed new tools are quite useful and practical. Some components of the results were assembled as free-software on an open-source platform to enable everyone in the world can use our result without limitations.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 25289150 - Dynamics of moving contacts of run-up tsunami waves
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
2015 - 2017
Watanabe Yasunori
This study provided a novel mechanical model imposed at a toe of tsunami running up over arbitrary ground conditions. This model has been confirmed to provide appropriate dynamic responses of the run-up waves and to estimate accurate flood areas. The specific research achievements are; (1)improvements of the imaging technique to measure dynamic three-dimensional water surfaces, (2) introduction of a phase-field model to three-dimensional fluid flow computations, (3) validations of the proposed model, and (4) establishing new computational framework for run-up tsunami computations. The proposed model has been applied to the two practical cases of tsunami floods, in urban area and river basin, observed in the 2011 Tohoku earthquake tsunami, which provided distinctive flooding processes depending on the ground conditions.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, Principal investigator, Competitive research funding, 15K14035 - Determinaion of damage index on long un-reinforced concrete structures relating to disaster prevention
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
01 Apr. 2012 - 31 Mar. 2015
YOKOTA Hiroshi; WATANABE Yasunori; SATO Yasuhiko; KATO Ema; HASHIMOTO Katsufumi
This research focused on how the comprehensive damage grading system is established for a long un-reinforced concrete structure along coastlines from the viewpoints of structural performance and functions of disaster prevention. Major damage induced in this type of structure is concrete cracking due to shrinkage of concrete and differential settlement of the structural body; accordingly, crack width, depth and position are categorized and modeled into the structural analysis tool. Moreover, shear transfer behavior between the crack surfaces was experimentally made clear. Finally, structural analysis taking into account the above behavior was carried out to quantify remaining structural performance of damaged structures. In conclusion, new criteria for damage evaluation have been proposed to access the function and performance of cracked un-reinforced concrete structures. These results may contribute to realize more effective and objective maintenance work.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 24360174 - Projection, impact assessment and adaptation of future coastal environment due to climate change
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
01 Apr. 2011 - 31 Mar. 2015
MASE Hajime; HASHIMOTO Noriaki; YAMADA Fumihiko; YOKOKI Hiromune; KUROIWA Masamitsu; NOGUCHI Kenji; KAWAI Hiroyasu; KITANO Toshikazu; MORI Nobuhito; WATANABE Yasunori; TAKEMI Tetsuya; YASUDA Tomohiro; OKU Yuichiro
Projection of typhoons, storm surges and waves were conducted for impact assessment of coastal environment in the future.
The observed sea level rise was analyzed based on the satellite observation and is 3 mm/year around Japan. Future changes of tropical cyclone activity was analyzed based on CMIP3 and CMIP5 results. The cyclogenesis number will be decreased and the tracks will be shifted to Eastward at the Northwest Pacific Ocean in the future. Risk of storm surge is estimated targeting Ise-wan (Vera) typhoon. The maximum level of storm surge and related uncertainty is discussed. The impact of coastal morphology was examined and shore line change based on standard sea level rise analysis is not sufficient for dynamic behavior of beach morphology.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Kyoto University, 23246090 - Development of a dynamic surface shape measurement system for liquid, solid and geographic surfaces
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
2012 - 2014
WATANABE Yasunori
A novel imaging system to measure three-dimensional surface shapes, based on the projector-camera system, was improved with aim to extend the practical applicability to coastal and hydraulic engineering. The additional algorisms to synchronize the projector and digital camera and to dynamically track the color patterns reflected on the surfaces were developed and introduced to the measurement system. The additional improvement for reducing optical errors associated with Lambert multiple dispersion system formed in liquid was also introduced to the system.
The developed measurement system was applied to experimental breaking waves to examine the reliability and capability to measure dynamic deformation of the free-surface. The measured results provided new aspects of the physical evaluation of transient free-surface forms of breaking waves.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, Principal investigator, Competitive research funding, 24656291 - Momentum and heat transfer governed by micro-mechanics between atmonphere and ocean
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
2012 - 2014
WATANABE Yasunori; YAMADA Tomohito; MORI Nobuhito; OTSUKA Junichi
A novel numerical simulator to compute local behaviors of sea sprays and entrained bubbles produced by micro ocean wave-breaking processes, based on the stochastic turbulence model, was developed in this study. The model was confirmed to reasonably reproduce heat and gas transfer through advection and diffusions processes via gas-liquid mechanical interactions.
Physical experiments for measuring the size distributions of sea-sprays and bubbles entrained into sea and the thermal radiation on the breaking-waves faces were performed in a wind wave flume. The momentum and heat transfer on the aerated ocean waves were found to be parametrized by the wind wave Reynolds number.The in-situ measurements for sea-sprays and air bubbles in ocean were also performed for characterizing mechanical contributions of the aerated ocean surface to the wave and current field.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, Competitive research funding, 24360196 - DeveIopment of numericaI wave fIume for a resiIient design of coastaI structures against violent waves
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
2009 - 2011
GOTOH Hitoshi; OKAYASU Akio; HIRAISHI Tetsuya; SHIGEMATSU Takaaki; KAWASAKI Koji; MUTSUDA Hidemi; WATANABE Yasunori; MORI Nobuhito; HARADA Eiji; HIRAYAMA Katsuya; KHAYYER Abbas; IKARI Hiroyuki
In this study,' Numerical Wave Flume' for a resilient design of coastal structures against violent waves was constructed by introducing free-surface flow models, including particle method. The characteristic of numerical models were investigated by 4 types of benchmark tests. And GPGPU computing was introduced tomake calculation as fast as possible. One of the tsunami disasters in the Tohoku-Pacific Ocean Earthquake was simulated by' Numerical Wave Flume' to examine its applicability
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Kyoto University, 21360235 - Bioluminescence-based imaging technique to measure fluid stresses
Grants-in-Aid for Scientific Research(挑戦的萌芽研究)
2009 - 2011
Yasunori WATANABE
The dinoflagellate Pyrocystis lunula emits light in response to water motion. The statistical features of the bioluminescence, emitted by P. lunula, owing to dynamic impact pressure and shear stress in oscillatory boundary layer flows over ripped bed were studied with the aim to develop a new imaging technique for measuring fluid stresses, pressure and shear, using plankton that emit light in response to mechanical stimulation. Since the flash intensity correlated with the both impact pressure and fluid strain rate, the instantaneous planar distribution of the fluid stresses can be estimated from video images of the bioluminescence in a fluid region by using the empirical relation determined in this study.
Ministry of Education, Culture, Sports, Science and Technology, 挑戦的萌芽研究, 北海道大学, Principal investigator, Competitive research funding, 21656120 - Solid-liquid recursive hydraulic model for flooding river flows
Grants-in-Aid for Scientific Research(基盤研究(A))
2007 - 2010
Yasuyuki SHIMIZU; Norihiro IZUMI; Yasunori WATANABE; Hirofumi TAKEBAYASHI; Yasuharu WATANABE; Hiroyasu YASUDA
This research presents numerical and analytical models describing sediment transport occurring at wide-ranging scales in flooding river flows ; local sand-laden turbulent flow, river-bed evolution at meandering length scale, morphological effects of permeable groundwater, and responses of flood to multiple-scaled watersheds.
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(A), 北海道大学, Coinvestigator not use grants, Competitive research funding, 19206052 - Micro and Macro scopic Characteristics of Sea Surface Wave Breaking
Grants-in-Aid for Scientific Research(基盤研究(C))
2007 - 2008
Nobuhito MORI; 渡部 靖憲; Yasunori WATANABE; Kousei TAKEHARA
沿岸域の砕波帯などで見られる水面波の砕波は, 時空間的に非定常かつ高速にマイクロスケールからセンチメートルスケールに渡る大きさの気泡や飛沫を多数発生させる. このような砕波により生成される気泡および飛沫を計測する手法を開発した. これを用いて, 砕波帯における気泡の計測を行い, 沿岸部における気泡の大きさや個数について調べ, 波浪条件との関係を明らかにした.
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(C), 大阪市立大学->京都大学, Coinvestigator not use grants, Competitive research funding, 19560516 - Impact pressure responses in aerated turbulent flows under violent breaking waves
Grants-in-Aid for Scientific Research(若手研究(B))
2006 - 2008
Yasunori WATANABE
沿岸域の波浪の砕波に伴い大量の空気が海中に混入すると共に空気中には飛抹が放出され、複雑な空気と海水が混合した乱流が発達する。この状態で波浪が海岸構造物に衝突するとき気体と液体との相互の作用から非常に強い衝撃力が発生し、被災の主要な原因となる。この衝撃力とエアレーションとの関係を最新の計測技術と計算技術によって定量化し、モデル化を行ないその信頼性と実用性を検証した。
Ministry of Education, Culture, Sports, Science and Technology, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 18760368 - Application of nonlinear dynamics to hydro-geomorphology
Grants-in-Aid for Scientific Research(基盤研究(B))
2004 - 2006
Yasuyuki SHIMIZU; 渡邊 康玄; 泉 典洋; 竹林 洋史; 渡部 靖憲
A weakly nonlinear analysis considering the interference between alternate bar and double-row bar has been developed. Findings show that when the two modes are on the same order, the mode cross interference controls development process of each wave and they cannot grow simultaneously. The development process of bars is strongly influenced of the mode cross interference. Hydraulic experiments and the weakly nonlinear analysis, by setting several hydraulic conditions under which either alternate bars or double-row bars formed, have been conducted to clarify a changing process of bar shape for...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 北海道大学, Coinvestigator not use grants, Competitive research funding, 16360242 - 砕波下の気固液混相乱流に対する局所相互作用の統計評価と沿岸物理環境境モデルの開発
科学研究費補助金(若手研究(B))
2003 - 2005
渡部 靖憲
・砕波が混入する気泡の砕波乱流への統計的寄与を明らかにするため,気液両相の速度の同時画像計測法を開発し,高解像計測を行った.この同時計測は,2つのデジタルビデオカメラに透過波数の異なる光学フィルターを設置し,蛍光着色した中立粒子と混入気泡にレーザー照射したそれぞれ励起光,反射光を選択的に記録し,Particle imaging velocimetryにより両相の速度分布を算定することで達成できる.この計測法の信頼性は,Ultrasonic Velocity Profilerとの比較によって検証された.気泡の混入が流体の乱流生成に統計的に大きな影響を与えると共に,気相の平均速度は流体の減速位相において流速の50%程度早い速度をもつ.これらの定量的に得られた統計量は砕波乱流のモデル化に使われる.・同一の画像計測法を底面砂の浮遊現象へ適用し,移動床上の浮遊イベント時の砂-流体相互作用の統計評価を行った.流体は底面近傍で上方へ向かう流れが卓越するが,砂はこれに追従せず形成されるリップルのクレスト方向へ移動する傾向がある.すなわち,浮遊砂は流体に対してパッシブな挙動をとらない.また,移動床上では,固定床と比べ境界層の剥離による力学的な影響が小さく,砂の浮遊に伴う流体の撹乱が乱れの生成の主要な役割を果たしていることが明らかになった.また,砂の浮遊にはこの撹乱に伴い強化された渦の再付着が大きくかかわっている.・砕波後のジェットの着水が生成する飛沫及び気泡を再現する数値モデルを開発した.これは,デカルト座標系上で自由水面での力学的境界条件を合理的に満足させ水面流速を適切に近似するものであり,正しく水面,渦そして表面張力による相互作用を評価するものである.このモデルにより,ジェットの着水に伴う二次ジェットの分裂及び局所的なキャビティーを再現し,砕波乱流のソースとなる水面の極近傍の渦生成を評価することが可能となった.
文部科学省, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 15760371 - Development of measurement method for investigating three dimensional turbulence structures in liquid-slid flow
Grants-in-Aid for Scientific Research(基盤研究(B))
2003 - 2005
Takaaki SHIGEMATSU; 渡部 靖憲; 竹原 幸生
The aim of this study is to develop a measurement technique for understanding three dimensional turbulence structures in liquid-solid flows. This study is composed of two processes ; one is for improvement of Super Resolution PIV developed by Takehara on time resolution and the other is for improvement of 3-D stereo PIV developed by Watanabe on space resolution.Although the super resolution PIV can measure the flow field with high space resolution by using many particle tracers for visualization, it did not have enough time resolution because we did not have enough capturing system. This pr...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 大阪市立大学, Coinvestigator not use grants, Competitive research funding, 15360269 - Design procedures for embedded structure considering seabed gonging of deformed sea ice
Grants-in-Aid for Scientific Research(基盤研究(B))
2003 - 2004
Hiroshi SAEKI; 渡部 靖憲
We developed a simulation method of Ice Scour Event considering probability distributions of various environmental parameters. As a result of calculations made under various conditions, order similar to those in the field observation data -the scour length of several tens of meters to several kilometers and the scour depth of several tens of centimeters to several meters -were found. Furthermore, due to the similarity to (reproducibility of) the comprehensive tendency/property of actual scour events, results that compared favorably with field observation results were obtained. Using the sim...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 北海道大学, Coinvestigator not use grants, Competitive research funding, 15360259 - Development of facilities for Control of pack ice movement and their design method
Grants-in-Aid for Scientific Research(基盤研究(A))
1999 - 2002
Hiroshi SAEKI; 橘 治国; 渡部 靖憲
In this research project, we obtained the following results :a) The coefficient of shearing force separated form the component of form drag force is obtained. In the case of ice jam, the form drag force can be ignored when l/H (l : length of ice floes, H : ice thickness) is mare than 450 because it is lero than 1% of the shearing force.b) Through the observation at Saroma lagoon, when ice floes are completely trapped in the ice boom, apart of the fluid force acting on the ice floes is transmitted via the ice floes to the ice boom, and the remainder of the fluid force due to arching of the i...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(A), 北海道大学, Coinvestigator not use grants, Competitive research funding, 11355023 - 砕波ジェット着水に起因する気泡生成機構と気泡の非定常剪断流への寄与
科学研究費補助金(奨励研究(A))
2000 - 2001
渡部 靖憲
本年度は、以下の研究を明らかにした。砕波ジェットのモデルとして貯水パイプにためられた水塊を瞬時に落下させ、水塊の水面への衝突に伴う混入気泡径及び発生から分裂さらに浮上にいたる気泡発達過程を評価する新たな解析法を開発した。気泡生成時に放射される音波をハイドロホンにより計測しウェーブレットパケット変換によりその発達過程を通じた気泡径を推算することによって発生する気泡はウェーバー数とフルード数によって5つの典型的なタイプに特徴化することができる。水中音を元にした計測法を多量の気泡が発生する実際の砕波に適用した。砕波フロントの到着直後、着水点の前後及びbubble clouds到達後で完全に異なる周波数帯の気泡音が確認された。砕波の局所的な流体運動に生成気泡の特性が大きく依存することが明らかになった。また、現地観測及び室内において生成微細気泡量の計測が行われ、実海域の気泡量が淡水を用いた室内実験より大きな値を示し、特にsawash zoneで急激な上昇が存在することが明らかになった。界面ステートに対する生成気泡の差異を界面活性剤を淡水中に混入させ室内実験を実行した。これにより安定した界面に発生する気泡は平均で非常に小さく、砕波形態に大きく依存することが明らかになった。上述の実験及び現地観測の結果により、砕波後の気泡の発達過程と気泡径について詳細な情報を得ることができた。これらの結果は、砕波後の気液二相流としての数値気泡モデルの定数を決定し気泡流計算を実行するために有効な情報である。
文部科学省, 奨励研究(A), 北海道大学, Principal investigator, Competitive research funding, 12750456 - 砕波帯内の3次元流体運動の時空間特性とカオス的挙動
科学研究費補助金(奨励研究(A))
1998 - 1999
渡部 靖憲
砕波帯内の3次元流速場・水粒子軌道の特性について,以下の重要な結論が得られた.1.中立粒子運動の3次元ビデオ解析・砕波時の混入気泡の影響を低減するため中立粒子に蛍光塗料を塗布しブラックライトを照射しビデオカメラを2次元水槽の上面及び側面からから撮影する3次元水粒子追跡実験方法を提案した.・統計解析及びwavelet解析により,砕波時にはほぼ2次元的であった流体運動が砕波過程を通して3次元性が強化され,2次元的な運動エネルギーが徐々にスケールダウンすることが明らかになった.・同様な解析により,水平及び鉛直方向に方向性をもつエネルギーが水深が浅くなるにつれ方向性を失うことが明らかになった.2.3次元Large Eddy Simulation・低レイノルズ数補正を行った高精度数値計算法を適用したLarge Eddy Simulationにより初めて砕波後の3次元流速場の数値的再現に成功した.・砕波ジェット着水直後に水平ローラー渦だけでなく縦渦及び旋回渦が生成されることが明らかになった.・生成された大規模渦整構造は,ボア領域において崩れ,発達した乱流に遷移する.この渦は戻り流れによって沖側に移流され次の砕波の3次元流速構造に大きな影響を与える.・砕波点近傍に移流された渦塊は連続する砕波に影響を与え,流速場及び水面形の3次元化を促進させる.この渦塊は砕波が繰り返されると共に強化されるので,徐々にジェットの着水以前に水面形が3次元化する.・計算領域にマーカーを配置し移流させることによって水粒子を追跡した.砕波フロント背後において斜め後方に軸を持つ渦を発見した.この渦は過去に実験的に気泡追跡によってのみ確認されている斜行渦の軌道と酷似しており,我々の発見した渦は斜行渦であると特定した.3.ビデオ解析による流体運動の3次元性に関する実験及び現地観測・実験水槽及び現地に水中カメラを固定し,混入気泡の映像から流体運動の3次元性を調べた.波の進行と直角方向に不規則な間隔で発生する発達した雲状の気泡が確認された.
文部科学省, 奨励研究(A), 北海道大学, Principal investigator, Competitive research funding, 10750382
