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研究者情報

マスター

アカウント（マスター）

  • 氏名

    高橋　裕介(タカハシ　ユウスケ), タカハシ　ユウスケ

所属（マスター）

  • 工学研究院　機械・宇宙航空工学部門　宇宙航空システム

所属（マスター）

  • 工学研究院　機械・宇宙航空工学部門　宇宙航空システム

独自項目

syllabus

  • 2021, 大学院共通授業科目（一般科目）：自然科学・応用科学, Inter-Graduate School Classes(General Subject):Natural and Applied Sciences, 修士課程, 大学院共通科目, Aerodynamics, airfoil, wing, transonic flows, supersonic flows, high enthalpy flows, high-temperature gas dynamics
  • 2021, 飛翔体工学特論, Introduction to Flight Dynamics, 修士課程, 工学院, 空気力学，翼型，翼，遷音速流れ，超音速流れ，高エンタルピー流れ，高温気体力学
  • 2021, 飛翔体工学特論, Introduction to Flight Dynamics, 博士後期課程, 工学院, 空気力学，翼型，翼，遷音速流れ，超音速流れ，高エンタルピー流れ，高温気体力学
  • 2021, 一般教育演習(ﾌﾚｯｼｭﾏﾝｾﾐﾅｰ), Freshman Seminar, 学士課程, 全学教育, 創成型科目、流れと構造の連成、剛体と柔軟構造体、空力弾性

researchmap

プロフィール情報

学位

  • 博士（工学）（九州大学）

プロフィール情報

対象リソース

業績リスト

研究キーワード

  • アーク加熱風洞   惑星大気再突入機   高エンタルピ流   

研究分野

  • フロンティア（航空・船舶） / 航空宇宙工学

経歴

  • 2021年04月 - 現在 北海道大学 大学院工学研究院 准教授
  • 2012年04月 - 2021年03月 北海道大学 大学院工学研究院 助教
  • 2016年04月 - 2017年03月 German Aerospace Center (DLR) Supersonic and Hypersonic Technologies Department of the Institute of Aerodynamics and Flow Technology Visiting Researcher
  • 2011年04月 - 2012年03月 独立行政法人宇宙航空研究開発機構 研究員

委員歴

  • 2015年04月 - 現在   日本航空宇宙学会   宇宙航行部門委員会委員
  • 2013年04月 - 2019年03月   日本機械学会 計算力学技術者資格認定事業委員会   熱流体力学分野小委員会 1級単相流 幹事
  • 2015年04月 - 2018年03月   日本機械学会北海道支部流体工学懇話会   幹事
  • 2014年04月 - 2016年03月   日本機械学会流体工学部門   講習会WG委員会委員
  • 2013年04月 - 2015年03月   日本機械学会流体工学部門   広報委員会委員

受賞

  • 2023年04月 北海道大学 北海道大学ディスティングイッシュトリサーチャー
     
    受賞者: 高橋裕介
  • 2021年03月 北海道大学大学院工学研究院 若手教員奨励賞
     
    受賞者: 高橋裕介
  • 2020年04月 文部科学省 令和２年度科学技術分野の文部科学大臣表彰 若手科学者賞
     大気再突入宇宙機の高速気流 とマルチフィジクスの研究 
    受賞者: 高橋裕介
  • 2018年04月 日本機械学会 奨励賞（研究）
     数値流体・電磁場解析による宇宙機の再突入ブラックアウト予測の研究 
    受賞者: 高橋裕介
  • 2018年03月 日本機械学会宇宙工学部門 宇宙賞
     
    受賞者: 展開型エアロシェル実験超小型衛星(EGG) チーム
  • 2016年10月 HPCI利用研究課題成果報告会 平成27年度実施課題における「京」を含むHPCI利用研究課題優秀成果賞
     「惑星大気再突入機に対する通信ブラックアウト評価ツールの構築」 
    受賞者: 高橋裕介
  • 2016年02月 一般財団法人コージェネレーションエネルギー高度利用センター 平成27年度コージェネ大賞 技術開発部門特別賞
     
    受賞者: 川崎重工業株式会社;北海道大学

論文

  • Yusuke Takahashi
    Journal of Sound and Vibration 118804 - 118804 2024年11月 [査読有り][通常論文]
  • Sanjoy Kumar Saha, Yusuke Takahashi
    Physics of Fluids 36 11 2024年11月01日 [査読有り][通常論文]
     
    Flexible aeroshells, featuring deformable membrane surfaces supported by pressurized gas, offer a novel re-entry system for high-altitude deceleration during re-entry. The flexibility of structural components introduces unique challenges in predicting aerodynamic behavior, as deformations can significantly alter the flow field, affecting pressure distribution and potentially causing aerodynamic instabilities. Therefore, coupled analysis is crucial to ensure the performance reliability of inflatable aeroshells. This study investigates the unsteady aerodynamic behavior, considering structural deformation in a two-way partitioned coupled manner in transonic flow. The dominant deformation patterns are identified using dynamic mode decomposition and the greedy compressive sensing algorithm. The findings reveal that the primary deformation pattern combines axial deformation and swing oscillation. The dominant oscillation frequencies remain different from the eigenfrequencies, indicating that the aerodynamic force is the primary driving force of such oscillations. The time evolution of these dominant modes indicates purely oscillatory behavior rather than increasing or decreasing trends. These insights are critical for the design and reliability assessment of inflatable aeroshells in varying aerodynamic environments.
  • Sanjoy Kumar Saha, Yusuke Takahashi
    AIAA Journal 1 - 16 2024年10月07日 [査読有り][通常論文]
     
    The deployable aeroshell, a contemporary reentry system, utilizes a thin flexible membrane surface sustained by pressurized gas to efficiently decelerate a reentry vehicle at high altitudes while enabling low-ballistic-coefficient flight. When an in-flight aerodynamic force is applied, the membrane structure undergoes large deformation that may affect its performance. Hence, a coupled analysis that considers the feedback effect of structural deformation is essential for accurately predicting the behavior of such reentry vehicles. In this study, a numerical framework for coupled aeroelastic analysis was constructed in a partitioned manner using open-source software to elucidate the combined effect of structural deformation and compressible flow dynamics and characterize the aerodynamic performance of reentry vehicles with inflatable structures. The results revealed that the membrane surface was deformed elastically by the aerodynamic force owing to the large difference in pressure distribution between the front and back of the aeroshell. Fluctuating behavior was observed in the aerodynamic coefficients owing to the small-amplitude oscillation of the capsule. This oscillation was induced by the large wake behind the vehicle. Several wrinkles and concave-shaped depressions formed on the membrane surface, which exhibited a circumferential movement tendency with time.
  • Tomoki Sakai, Yusuke Takahashi
    Aerospace Science and Technology 153 109418 - 109418 2024年10月 [査読有り][通常論文]
  • Takashi Miyashita, Yuji Sugihara, Yusuke Takahashi, Yasunori Nagata, Hisashi Kihara
    Journal of Physics D: Applied Physics 57 32 325206 - 325206 2024年05月20日 [査読有り][通常論文]
     
    Abstract Communication blackouts during atmospheric reentry pose significant challenges to the safety and adaptability of spacecraft missions. This phenomenon, caused by the attenuation of electromagnetic waves by the plasma surrounding the spacecraft, disrupts communication with ground stations or orbiting satellites. Therefore, it is crucial to decrease the plasma density in the vicinity of the spacecraft to ensure an unobstructed electromagnetic wave communication path. This study proposes a methodology that involves the injection of gas from the vehicle’s wall to create an insulating layer near the surface. This thin layer maintains lower temperatures and reduced plasma density, enabling electromagnetic wave propagation without attenuation. Practical experiments were conducted in an arc-heating facility to simulate atmospheric reentry conditions. The results of the experiments provided empirical evidence of the effectiveness of the technique in mitigating communication blackout phenomena. Numerical fluid analysis within the wind tunnel chamber validated the formation of an air film layer near the experimental model owing to the injected gas. Schlieren imaging revealed distinctive jet shapes, which corroborated the findings of the numerical analysis. The wind tunnel tests that simulated atmospheric reentry environments confirmed the formation of an air film layer through gas injection, which substantiates the reduction in communication blackout. These results have the potential to improve communication reliability in space transport.
  • Hideto Takasawa, Tomoya Fujii, Yusuke Takahashi, Takahiro Moriyoshi, Hiroki Takayanagi, Yasunori Nagata, Kazuhiko Yamada
    CEAS Space Journal 2024年04月26日 [査読有り][通常論文]
  • Takashi Miyashita, Hideto Takasawa, Yusuke Takahashi, Lars Steffens, Ali Gülhan
    AIAA Journal 62 2 437 - 448 American Institute of Aeronautics and Astronautics (AIAA) 2024年02月 [査読有り][通常論文]
     
    Communication blackouts during the atmospheric reentry phase are a significant challenge, as flight data are lost due to interruptions caused by plasma gas generated by aerodynamic heating. This study explores a novel mitigation method using an air film, a thin insulating coolant layer on the surface. The researchers successfully reduced the reentry blackout by employing a gas injection system. Through a coupled approach using computational fluid dynamics and a frequency-dependent finite-difference time-domain method, the plasma flow properties and electromagnetic propagation were analyzed around a test model in a wind tunnel in DLR (German Aerospace Center). The numerical results indicated that the injected nitrogen gas formed an insulating air film layer on the surface. The thin layer advected backward, maintaining a low temperature without ionization, and covered the object in the wake region. The electromagnetic waves propagated and reached a distant area because the electron density was low. It means that the air film layer acted as a propagation window for the telecommunication waves. Thus, communication blackouts will be avoidable because electromagnetic waves can transmit through the air-film layer. It concluded that the air film effect, developed as a thermal protection technique, is a novel mitigation scheme for reentry blackouts.
  • 宮下岳士, 高澤秀人, 玉井亮多, 平田耕志郎, 若林海人, 吉雄忠行, 山本春佳, 丹野茉莉枝, 高橋裕介, 永田靖典, 山田和彦
    宇宙航空研究開発機構研究開発報告: 大気球研究報告 JAXA-RR-23-003 59 - 75 2024年02月 [査読有り][通常論文]
  • Hideto TAKASAWA, Tomoya FUJII, Koshiro HIRATA, Takahiro MORIYOSHI, Yusuke TAKAHASHI, Yasunori NAGATA, Kazuhiko YAMADA
    Mechanical Engineering Journal 11 3 24-00053  2024年 [査読有り][通常論文]
  • Yu Minghao, Qiu Zeyang, Yusuke Takahashi
    Physics of Fluids 35 5 2023年05月01日 [査読有り]
     
    Radio frequency blackout indicates the communication interruption between signal monitoring sites and re-entry vehicles; it is a serious threat to the safety of astronauts and the space exploration missions. In this study, a surface catalytic model coupled with a thermochemical non-equilibrium computational fluid dynamic model is developed to study the catalytic wall effect on the plasma sheath of a hypersonic re-entry vehicle. The mechanism of the surface catalytic effect on the plasma sheath of a re-entry capsule is revealed by a comparative study. The flow-field characteristics simulated under conditions of the full-catalytic and non-catalytic walls are compared and discussed for the hypersonic atmospheric re-entry capsule at different altitudes. The chemical and physical mechanisms behind the surface catalytic effect of the re-entry capsule are analyzed. The experimental data of Radio Attenuation Measurement-C-II are used to validate the numerical model established in the present study. It is found that the numerical results simulated with the fully catalytic wall are more consistent with the experimental data. Near the capsule wall, the mole fractions of the species N, O, N+, and O+ decrease as the catalytic recombination coefficient increases. Because of the surface catalytic effect, the communication black is mitigated due to the reduction of the electron number density in the wake zone of the capsule.
  • 高澤秀人, 末永陽一, 宮下岳士, 平田耕史郎, 若林海人, 高橋裕介, 永田靖典, 山田和彦
    JAXA Research and Development Report JAXA-RR-22-008 37 - 50 2023年02月 [査読有り][通常論文]
  • Sanjoy Kumar Saha, Junki Tobari, Yusuke Takahashi, Nobuyuki Oshima, Takahiro Moriyoshi, Kazuhiko Yamada, Ryoichi Shibata
    Aerospace Science and Technology 133 108112 - 108112 2023年02月 [査読有り]
  • Minghao Yu, Zeyang Qiu, Bowen Zhong, Yusuke Takahashi
    Physics of Fluids 34 12 126103 - 126103 AIP Publishing 2022年12月 [査読有り]
     
    A multi-physics thermochemical non-equilibrium model is established to study the flow characteristics of the plasma sheath around an atmospheric reentry demonstrator. This model includes the tight coupling of Navier–Stokes equations, 54 chemical reactions of air, and a four-temperature model. The processes of dissociation, ionization, and the internal energy exchanges of air components were successfully simulated during aerodynamic heating of the reentry vehicle. The distributions of plasma sheath temperature, the molar fraction of air species, stagnation pressure, surface pressure, and electron number density around the reentry vehicle were obtained at different flight altitudes. Additionally, to validate the numerical model developed in this study, the flow characteristics of the Radio Attenuation Measurement-C-II (RAM-C-II) vehicle are also simulated and then compared with corresponding experimental data. They show good consistency in general. It is found that when the vehicle is at a high flight altitude, there is a strong thermochemical non-equilibrium phenomenon around the vehicle. However, the plasma sheath tends to be in local thermal equilibrium at a low flight altitude. The distance from the shock layer to the stagnation point decreases with a decrease in reentry altitude from 90 to 65 km but increases with a decrease from 65 to 40 km. The electron number density in the shock layer is maximum. The distribution of the electron number density in the wake region differs significantly at different flight altitudes.
  • Yusuke Takahashi
    IEEE Transactions on Aerospace and Electronic Systems 58 5 4070 - 4082 2022年10月 [査読有り]
  • Yusuke Takahashi, Masahiro Saito, Nobuyuki Oshima, Kazuhiko Yamada
    Acta Astronautica 194 301 - 308 2022年05月 [査読有り][通常論文]
  • Yusuke Takahashi, Hideto Takasawa, Kazuhiko Yamada, Takayuki Shimoda
    Journal of Physics D: Applied Physics 55 23 235205 - 235205 2022年03月02日 [査読有り][通常論文]
     
    Abstract An arc-heated wind tunnel is one of the most important facilities to reproduce the high-temperature environment during atmospheric entry for plasma studies and spacecraft development. However, the properties of the plasma flow cannot be determined easily, because of the complex physical phenomena, such as arc discharge and supersonic expansion, occurring inside the tunnel. The shock-layer structure should be clarified to evaluate the aerodynamic characteristics, communication conditions, and thermal- protection performance in a high-temperature environment. In this study, shock-layer spectroscopic measurements of a plasma flow in a 1 MW-class arc-heated wind tunnel were performed. The γ-band system spectra of nitric oxide (NO) molecules in the ultraviolet region were measured, and the rotational temperature was determined via spectral fitting through comparison with numerical spectra. The rotational temperature of the NO molecules in the shock layer was 6,620±350 K, whereas that in the free jet was much lower at 770±60 K. This difference is attributed to the increase in translational temperature by flow stagnation across the shock wave, followed by the increase in rotational temperature owing to energy relaxation. A computational science approach revealed the detailed structure of the flow through comparisons with the spectroscopic measurement data. The wind tunnel flow became hypersonic with high temperature and low pressure due to the expansion and acceleration at the nozzle and test chamber. Although the temperature increased across the shock wave, the chemical reaction progressed slowly owing to the low-pressure environment. The rotational temperature in the shock layer increased with the translational temperature; this agrees with the trend of the measurement results. The arc-heated flow was found to be in strong thermo- chemical nonequilibrium in the shock layer. Through this study, a detailed structure of arc-heated flow was revealed and its methodology was also proposed.
  • Minghao Yu, Zeyang Qiu, Bo Lv, Yusuke Takahash
    Mathematics 10 5 832 - 846 2022年 [査読有り][通常論文]
  • Hideto Takasawa, Yusuke Takahashi, Nobuyuki Oshima, Hisashi Kihara
    Journal of Physics D: Applied Physics 54 22 225201 - 225201 IOP Publishing 2021年03月08日 [査読有り]
     
    The reentry blackout phenomenon, which is the communication cut-off between the re-entry vehicle and ground station, is a crucial problem that needs to be addressed. To improve safety during reentry, a new mitigation method was proposed using the surface catalysis effect. However, this method has not been investigated extensively by experimental methods. In this study, we experimentally demonstrated the mitigation method using a 1 MW arc-heated wind tunnel and numerically clarified the mitigation mechanism. As a demonstration experiment, communication tests were conducted to compare the two cases. In the first case, a ceramic surface was used as a low catalytic wall, whereas in the second case, a copper surface was used as a high catalytic wall in the arc-heated wind tunnel. The experimental results indicated that the blackout occurred when alumina was used as the low catalytic wall. On the other hand, for the high catalytic wall using copper, blackout was avoided. The tests were reproduced in the wind tunnel using a numerical simulation technique. From the simulation results, the mitigation mechanism suggested that: (a) the number of nitrogen and oxygen atoms decreased due to catalysis; (b) forward reactions of electron impact ionization were suppressed due to the decrease in the number of atoms; and (c) the suppression of reactions decreased the number of electrons, thereby mitigating the reentry blackout. In addition, the numerical simulations performed on the reentry plasma around the re-entry capsule suggested that the mitigation mechanisms between the arc-heated wind flow and reentry plasma were similar despite the different airflow conditions.
  • Yusuke Takahashi, Naoya Enoki, Taiki Koike, Mayuko Tanaka, Kazuhiko Yamada, Takayuki Shimoda
    AIAA Journal 59 1 263 - 275 2021年01月 [査読有り]
     
    The flow enthalpy of an arc-heated wind tunnel is an important parameter for reproducing planetary entry and performing heating tests. However, its distribution is insufficiently clarified, owing to complicated phenomena, such as arc discharge and supersonic expansion. In this paper, the authors assess the enthalpy of an arc-heated flow in a large-scale facility based on measurements and computational results. The flow enthalpy of high-temperature gases, which comprised thermal, chemical, kinetic, and pressure components, was reconstructed based on the measured rotational temperature, heat flux, and impact pressure, in addition to the computational science approach. The rotational temperature of nitric oxide molecules was obtained using emission spectroscopic measurements of band spectra in the near-ultraviolet range. A numerical model was developed and validated based on measured data. The results indicated that the model efficiently reproduced the arc discharge behavior in the heating section and the thermochemical nonequilibrium in the expansion section. It was discovered that the dominant components of the arc-heated flow in the test section were the chemical and kinetic components. The flow enthalpy exhibited a nonuniform distribution in the radial direction. The authors conclude that the flow enthalpy of the core is approximately 28 MJ/kg at the nozzle exit.
  • Yusuke Takahashi, Tatsushi Ohashi, Nobuyuki Oshima, Yasunori Nagata, Kazuhiko Yamada
    Physics of Fluids 32 7 075114 - 075114 AIP Publishing 2020年07月01日 [査読有り]
     
    Aerodynamic instability in the attitude of an inflatable re-entry vehicle in the subsonic regime has been observed during suborbital re-entry. This causes significant problems for aerodynamic decelerators using an inflatable aeroshell; thus, mitigating this problem is necessary. In this study, we revealed the instability mechanism using a computational science approach. To reproduce the in-flight oscillation motion in an unsteady turbulent flow field, we adopted a large-eddy simulation approach with a forced-oscillation technique. Computations were performed for two representative cases at transonic and subsonic speeds that were in stable and unstable states, respectively. Pitching moment hysteresis at a cycle in the motion was confirmed for the subsonic case, whereas such hysteresis did not appear for the transonic case. Pressures on the front surface and in the wake of the vehicle were obtained by employing a probe technique in the computations. Pressure phase delays at the surface and in the wake were confirmed as the pitch angle of the vehicle increased (pitch up) and decreased (pitch down), respectively. In particular, we observed that the wake structure formed by a large recirculation behavior significantly affected the pressure phase delay at the rear of the vehicle. The dynamic instability at subsonic speed resulted from flows that could not promptly follow the vehicle motion. Finally, the damping coefficients were evaluated for the design and development of the inflatable vehicle.
  • Yusuke Takahashi, Naoya Enoki, Hideto Takasawa, Nobuyuki Oshima,
    Journal of Physics D: Applied Physics 53 23 235203 - 235203 2020年04月 [査読有り][通常論文]
     
    Radio frequency (RF) blackout during atmospheric reentry leads to the cutoff of communication with ground stations and/or data-relay satellites. This causes significant problems during reentry, and thus, mitigation methods have been in high demand. In this study, we numerically demonstrate a novel method for mitigating the RF blackout using surface catalysis effects. Plasma flow behavior and electromagnetic wave propagation around a reentry vehicle were investigated in detail. The approach couples computational fluid dynamics and a frequency-dependent finite-difference time-domain method. The computations were performed with a massive parallelization technique using a large computer. The computed results were compared for cases imposing low and full catalysis conditions on a surface boundary. The investigation revealed that the surface catalysis effects reduce the RF blackout. Atomic species, dissociated across a shock wave formed in front of the vehicle, were recombined on the vehicle surface through surface catalysis. These molecules, flowing into a wake region at the vehicle's rear, caused recombinations of electrons, originally generated in the shock layer. Therefore, a decrease in electrons was observed in the wake region and a wake path, which allows the propagation of electromagnetic waves, was formed. This complicated behavior of the molecules and electrons, induced by the surface catalysis, resulted in mitigation of the RF blackout.
  • Naoya Enoki, Yusuke Takahashi, Nobuyuki Oshima, Kazuhiko Yamada, Kojiro Suzuki
    AIP Conference Proceedings 2132 100002  American Institute of Physics 2019年08月05日 [査読有り][通常論文]
     
    An inflatable nano-satellite with thin-membrane aeroshell, "EGG", was deployed from the International Space Station at an altitude of approximately 400 km, as part of an orbital deployment mission in 2017. After flight on the low Earth orbit (LEO) for 120 days, EGG successfully reentered Earth's atmosphere and burned out according to mission schedule. During the mission period, surface temperatures of the membrane aeroshell of EGG were measured using thermocouples. The measurement data was sent to the ground station using Iridium short burst data communication. There has not been sufficient investigation of the aerodynamic heating environment of such inflatable vehicles. In this paper, the heat flux on membrane aeroshell was revealed, based on the measured temperature data and a heat conduction simulation technique. In addition, heat flux distributions at an altitude of 120 km were numerically evaluated using the Direct Simulation Monte Carlo (DSMC) method, for cases where the angle of attack was between 0 and 180 degrees. From the reconstructed heat flux history and the DSMC analysis results, it was found that the heat flux on the inflatable torus was higher than that on the membrane aeroshell. Additionally, it was concluded that EGG was in the heating environment of approximately 3-4 kW/m(2) at an altitude of 110 km.
  • Yusuke Takahashi, Taiki Koike, Nobuyuki Oshima, Kazuhiko Yamada
    Aerospace Science and Technology 92 858 - 868 2019年 [査読有り][通常論文]
     
    An inflatable aerodynamic decelerator with a membrane aeroshell is a promising key technology in the reentry, descent, and landing phases of future space transportation. The membrane aeroshell is generally deformed by the in-flight aerodynamic force; however, the effects of the deformation on the aerodynamic heating are unclear. Here, we investigated aerodynamic heating for an inflatable reentry vehicle, Titans, in the hypersonic regime using flow field simulation coupled with structural analysis. Thermochemical nonequilibrium flows around the Titans with a deformed membrane aeroshell were reproduced numerically for an angle of attack (AoA) values between 0 degrees and 40 degrees. The maximum displacements of the membrane aeroshell by deformation at the AoAs of 0 degrees and 40 degrees were 6.7% and 6.6% of the diameter of the Titans, respectively. The difference in heat fluxes between the deformed and rigid shapes was a remarkable 188.8% for a 0 degrees AoA owing to the considerable changes in the front shock wave shape. Meanwhile, it was indicated that membrane deformation at an AoA of 40 degrees insignificantly affected the peak heat flux value on the inflatable torus because the considerable change in the shock wave shape observed for the case of 0 degrees AoA did not occur. It was found that local wrinkles on the membrane aeroshell were formed by deformation, thus causing the heat flux to increase owing to an increase in local temperature gradient on the surface. (C) 2019 Elsevier Masson SAS. All rights reserved.
  • Yusuke Takahashi, Manabu Matsunaga, Nobuyuki Oshima, Kazuhiko Yamada
    Journal of Spacecraft and Rockets 56 2 577 - 585 2019年 [査読有り][通常論文]
     
    The drag coefficient for inflatable reentry vehicles shows discrepancies between a wind tunnel experiment and a flight test in a transonic regime. These discrepancies exist in the drag decrease behavior in the transonic regime and local minimum values of drag above the sonic speed in a wind tunnel. Hence, the present paper focuses on uncovering the reasons and mechanisms behind the same and investigates transonic flowfields around a vehicle by using a transonic wind tunnel and the computational fluid dynamics approach. Several test models with diameters ranging from 56 to 96 mm are used to quantitatively evaluate the effects of scale and a sting attached on the rear. Aerodynamic coefficients, pressures at the rear of the model, and density-gradient distributions are measured for operation conditions of freestream Mach numbers ranging between 0.8 and 1.3. In addition, detailed distributions of the flowfield properties are clarified using the computational fluid dynamics method, which is validated by the experimental data. The results indicate that a sting behind the test models reduces the steep drag decrease at transonic speeds and that shock waves reflected on the test-section walls of the wind tunnel result in local minimum values at supersonic speeds.
  • 田中真由子, 山田和彦, 高橋裕介, Yu Minghao, 手塚亜聖
    日本航空宇宙学会論文集 67 2 42 - 48 2019年 [査読有り][通常論文]
  • 福田泰久, 荒谷貴洋, 高橋裕介, 山田和彦, 小柳潤
    航空宇宙技術 18 127 - 131 2019年 [査読有り][通常論文]
  • Yusuke Takahashi, Kazuhiko Yamada
    Acta Astronautica 152 437 - 448 2018年11月 [査読有り][通常論文]
     
    The aerodynamic heating of an inflatable reentry vehicle, which is one of the innovative reentry technologies, was numerically investigated using a tightly coupled approach involving computational fluid dynamics and structure analysis. The fundamentals of a high-enthalpy flow around the inflatable reentry vehicle were clarified. It was found that the flow fields in the shock layer formed in front of the vehicle were strongly in a chemical nonequilibrium state owing to its low-ballistic coefficient trajectory. The heat flux tendencies on the surface of the vehicle were comprehensively investigated for various effects of the vehicle shape, surface catalysis, and turbulence via a parametric study of these parameters. In addition, based on the present results of the computational approach, a new heating-rate method was developed to calculate the heat flux of the nonequilibrium flow. It was demonstrated that the method could well-reproduce the heat flux on the inflatable reentry vehicle.
  • Tatsushi Ohashi, Yusuke Takahashi, Hiroshi Terashima, Nobuyuki Oshima
    Journal of Fluid Science and Technology 13 3 JFST0020 - JFST0020 2018年10月 [査読有り][通常論文]
     
    An inflatable membrane reentry vehicle has been developed as one of the innovative reentry technologies. A suborbital reentry demonstration using a sounding rocket was carried out in 2012. Contrary to the result of a preliminary study, the vehicle always had an angle of attack (AoA) during its reentry. In addition, the amplitude of AoA gradually increased as altitude decreased, and the vehicle rotated vertically under Mach number of 0.1 (M0.1). As a first step to clarify the cause of attitude instability and vertical rotation, the aerodynamic characteristics, that concern static stability, are numerically investigated. Numerical simulations were carried out for the cases of Mach 0.9 (M0.9), 0.6 (M0.6), 0.3 (M0.3), and 0.1 (M0.1) and pitching moment coefficients (CM) were obtained. Analysis software "RG-FaSTAR" for M0.9, and "FrontFlow/red" for M0.6, M0.3 and M0.1, are used, respectively. Large eddy simulation (LES) was performed using the standard Smagorinsky model to resolve highly unsteady flow features. Because the slope of CM with respect to AoA was negative for all cases, it was found that the vehicle is statically stable. For M0.9, M0.6 and M0.3 cases, absolute values of CM were almost the same. On the other hand, for M0.1, CM had a particularly large value, because the surface pressure distribution on rear side of the vehicle was different from the other cases. This difference was attributed to the separation point on the lower torus moving backward and turbulence in wake being enhanced with a decrease in Mach number and an increase in the Reynolds number.
  • Yusuke Takahashi, Kazuhiko Yamada
    Journal of Thermophysics and Heat Transfer 32 3 547 - 559 2018年 [査読有り][通常論文]
     
    In sample-return missions, the reentry velocity of a sample-return capsule is expected to be approximately 15 km/s however, the reentry velocity of the Hayabusa sample-return capsule was 11.8 km/s. Strong aerodynamic heating caused by a high velocity can damage the capsule during reentry. To overcome this, two designs of highvelocity reentry capsules were proposed. In one design, a rigid flare was attached to decrease the ballistic coefficient by increasing the front projected area. In the other design, the conventional Hayabusa sample-return capsule was used with no modifications. In this study, the aerodynamic heating of the high-velocity reentry capsules and the Hayabusa sample-return capsule was analyzed using numerical simulations. Plasma flow in the shock layer at the front of the capsules and expansion flow in the wake region around the capsules were investigated. The profiles of convective and radiative heat fluxes on the surfaces of these capsules were predicted. The heat fluxes at the stagnation points predicted by the present numerical simulation were in good agreement with that of the empirical models. At the strongest aerodynamic-heating altitude, the total heat fluxes at the rear of the high-velocity reentry capsules and the Hayabusa sample-return capsule were approximately 2% of those in front of the capsules.
  • Minseok Jung, Hisashi Kihara, Ken-Ichi Abe, Yusuke Takahashi
    Physics of Plasmas 25 1 013507  2018年01月01日 [査読有り][通常論文]
     
    A numerical simulation model of plasma flows and electromagnetic waves around a vehicle was developed to predict a radio frequency blackout. Plasma flows in the shock layer and the wake region were calculated using a computational fluid dynamics technique with a three-dimensional model. A finite-catalytic wall condition known to affect plasma properties, such as the number density of electrons, was considered for accurate prediction. A parametric study was performed to investigate the effect of uncertainty in the chemical reaction rate model on evaluating a radio frequency blackout. The behavior of electromagnetic waves in plasma was investigated using a frequency-dependent finite-difference time-domain method. Numerical simulations of reentry blackout were performed for the Atmospheric Reentry Demonstrator mission at various altitudes. The plasma flows and the complex movement of electromagnetic waves around the Atmospheric Reentry Demonstrator vehicle were clarified. The predicted signal loss profile was then directly compared with the experimental flight data to validate the present models. The numerical results generally reproduced the trends over altitudes of the measured data. It is suggested that the present simulation model can be used to investigate the radio frequency blackout and signal loss of electromagnetic waves in the communication of a reentry vehicle. It was confirmed that high associative ionization reaction rates contribute to reducing the electron density in the wake region and radio frequency blackout. It is suggested that the accuracy of predicting the signal loss improved when considering the uncertainty in the chemical reaction model for associative ionizations.
  • 高橋裕介, 松永学, 大島伸行, 山田和彦
    日本航空宇宙学会誌（特集） 65 12 370 - 376 2017年12月 [査読有り][通常論文]
  • Yusuke Takahashi, Burkard Esser, Lars Steffens, Ali Guelhan
    PHYSICS OF PLASMAS 24 12 123509  2017年12月 [査読有り][通常論文]
     
    In this study, we developed an analytical model for the flow field in the Huels-type arc-heated wind tunnel (L2K) of the German Aerospace Center. This flow-field model can be used to accurately reproduce the discharge behavior in the heating section and expansion in the nozzle section of L2K. It includes the radiation transport and turbulent flow as well as thermochemical nonequilibrium models, which are tightly coupled with electric field calculations. In addition, we considered the turbulent diffusion model for the mass conservation of the species and performed numerical simulations for several cases with and without the turbulent diffusion model. Computations were conducted to obtain the general characteristics of an arc-heated flow containing an arc discharge and supersonic expansion. We verified that radiation and turbulence play important roles in the transfer of heat from the high-temperature core flow to the outer cold gas in the heating section of L2K. In addition, we performed parametric studies that involved varying the degree of turbulent diffusion. The results showed that turbulent diffusion has a large influence on the formation of the arc discharge in the heating section and on the enthalpy distribution at the nozzle exit. Published by AIP Publishing.
  • Landon Kamps, Yuji Saito, Ryosuke Kawabata, Masashi Wakita, Tsuyoshi Totani, Yusuke Takahashi, Harunori Nagata
    Journal of Propulsion and Power 33 6 1369 - 1377 American Institute of Aeronautics and Astronautics 2017年11月 [査読有り][通常論文]
  • 山田和彦, 鈴木宏二郎, 安部隆士, 秋田大輔, 今村宰, 永田靖典, 高橋裕介
    日本航空宇宙学会誌（特集） 65 11 333 - 340 一般社団法人 日本航空宇宙学会 2017年11月 [査読有り][通常論文]
     

    展開型柔軟エアロシェルは，将来の革新的な大気圏突入システムとして期待されている．我々のグループでは，カプセル形状の本体の周りに取り付けられる円錐形状の薄膜フレアと，その外周に取り付けられたガス圧で展開し形状を維持するインフレータブルリングで構成される，薄膜フレア型の展開型柔軟エアロシェルに注目して研究開発を進めてきた．本技術に対する我々の研究開発活動の特徴は，大気球実験，観測ロケット実験，国際宇宙ステーション/「きぼう」からの超小型衛星の放出機会など，各種フライト機会を利用し，その都度，フライト実験機を開発し，実際に飛行させることで，各要素技術のフライト環境での実証や大気圏突入システムとしての機能検証を行ってきた点にある．本稿では，展開型大気圏突入機の研究開発の紹介とともに，我々がこれまでに行ってきた各種フライト試験の概要について紹介する．

  • Yusuke Takahashi, Dongheun Ha, Nobuyuki Oshima, Kazuhiko Yamada, Takashi Abe, Kojiro Suzuki
    JOURNAL OF SPACECRAFT AND ROCKETS 54 5 993 - 1004 2017年09月 [査読有り][通常論文]
     
    A flight experiment of an inflatable reentry vehicle, equipped with a thin-membrane aeroshell deployed by an inflatable torus structure, was performed using a Japan Aerospace Exploration Agency S-310-41 sounding rocket. The drag coefficient history was evaluated by analyzing the acceleration of the vehicle with the atmospheric density and temperature using a global reference atmospheric model. The vehicle successfully demonstrated deceleration. During the reentry flight, the position, velocity, and acceleration of the vehicle were obtained by using the Global Positioning System. The experimental drag coefficient had an almost constant value of 1.5 in the supersonic region but decreased to 1.0 in the subsonic region. In the transonic region, a steep decrease of the drag coefficient was confirmed. To study the detailed aerodynamics for the reentry vehicle, flowfield simulations were conducted with computational fluid dynamics techniques. The aerodynamic force acting on the vehicle was investigated with the measured data throughout the supersonic and subsonic regions. In the flowfield simulation, the computed result for the drag coefficient showed reasonable agreement with the experimental one. In addition, a compressible effect in front of the vehicle was seen to appear in the supersonic region and a vortex ring at the rear of the vehicle was formed in the subsonic region.
  • Minseok Jung, Minseok Jung, Hisashi Kihara, Hisashi Kihara, Ken Ichi Abe, Ken Ichi Abe, Yusuke Takahashi
    47th AIAA Fluid Dynamics Conference, 2017 2017年01月01日 [査読有り][通常論文]
     
    © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. Numerical simulations of plasma flows and electromagnetic waves around a reentry vehicle were performed to estimate the radio-frequency blackout. The plasma flows in the shock layer and wake region were calculated using computational fluid dynamics technique. The simulation of electromagnetic waves around a reentry vehicle was conducted using a frequency-dependent finite-difference time-domain method with the plasma properties obtained by computational fluid dynamics. The numerical simulations were performed for the atmospheric reentry demonstrator at various altitudes based on the reentry orbit data. Three cases of the numerical simulations, i.e., an axisymmetric model, a three-dimensional model with non-catalytic wall and finite-catalytic wall, were performed for evaluating the effects of angle of attack and catalytic wall on the radio-frequency blackout. The formations for the number density of electrons that is an important parameter in evaluating the radio-frequency blackout were greatly changed by these three cases. The simulation model was validated based on the signal loss history of the experimental flight data. The simulation results using a three-dimensional model with finite-catalytic wall showed better agreement with the measured results compared to other two cases.
  • Keisuke Tanaka, Tomonari Sato, Nobuyuki Oshima, Jiun Kim, Yusuke Takahashi, Yasunori Iwai
    PROCEEDINGS OF THE ASME POWER CONFERENCE JOINT WITH ICOPE-17, 2017, VOL 1 2017年 
    Turbulent combustion flows in the partially premixed combustion field of a dry low-emission gas-turbine combustor were investigated numerically by large-eddy simulation with a 2-scalar flamelet model. Partially premixed combustion was modelled with 2-scalar coupling based on the conservative function of the mixture fraction and the level set function of the premixed flame surface; the governing equations were then used to calculate the gas temperature in the combustion field with flamelet data. A new combustion model was introduced by defining a nondimensional equilibrium temperature to permit the calculation of-adiabatic flame temperatures in the combustion field. Furthermore, a conventional G-equation was modified to include spatial gradient terms for the adiabatic flame temperature to facilitate smooth propagation of a burnt state region in a predominantly diffusion flame. The effect of flame curvature was adjusted by means of an arbitrary parameter in the equation. The simulation results were compared with those from an experiment and a conventional model. Qualitative comparisons of the instantaneous flame properties showed a dramatic improvement in the new combustion model. Moreover, the experimental outlet temperature agreed well with that predicted by the new model. The model can therefore reproduce the propagation of a predominantly diffusion flame in partially premixed combustion.
  • Minghao Yu, Kazuhiko Yamada, Yusuke Takahashi, Kai Liu, Tong Zhao
    PHYSICS OF PLASMAS 23 12 123523  2016年12月 [査読有り][通常論文]
     
    A numerical model for simulating air and nitrogen inductively coupled plasmas (ICPs) was developed considering thermochemical nonequilibrium and the third-order electron transport properties. A modified far-field electromagnetic model was introduced and tightly coupled with the flow field equations to describe the Joule heating and inductive discharge phenomena. In total, 11 species and 49 chemical reactions of air, which include 5 species and 8 chemical reactions of nitrogen, were employed to model the chemical reaction process. The internal energy transfers among translational, vibrational, rotational, and electronic energy modes of chemical species were taken into account to study thermal nonequilibrium effects. The low-Reynolds number Abe-Kondoh-Nagano k-epsilon turbulence model was employed to consider the turbulent heat transfer. In this study, the fundamental characteristics of an ICP flow, such as the weak ionization, high temperature but low velocity in the torch, and wide area of the plasma plume, were reproduced by the developed numerical model. The flow field differences between the air and nitrogen ICP flows inside the 10-kW ICP wind tunnel were made clear. The interactions between the electromagnetic and flow fields were also revealed for an inductive discharge. Published by AIP Publishing.
  • Minseok Jung, Hisashi Kihara, Ken-ichi Abe, Yusuke Takahashi
    JOURNAL OF THE KOREAN PHYSICAL SOCIETY 68 11 1295 - 1306 2016年06月 [査読有り][通常論文]
     
    A three-dimensional numerical simulation model that considers the effect of the angle of attack was developed to evaluate plasma flows around reentry vehicles. In this simulation model, thermochemical nonequilibrium of flowfields is considered by using a four-temperature model for high-accuracy simulations. Numerical simulations were performed for the orbital reentry experiment of the Japan Aerospace Exploration Agency, and the results were compared with experimental data to validate the simulation model. A comparison of measured and predicted results showed good agreement. Moreover, to evaluate the effect of the angle of attack, we performed numerical simulations around the Atmospheric Reentry Demonstrator of the European Space Agency by using an axisymmetric model and a three-dimensional model. Although there were no differences in the flowfields in the shock layer between the results of the axisymmetric and the three-dimensional models, the formation of the electron number density, which is an important parameter in evaluating radio-frequency blackout, was greatly changed in the wake region when a non-zero angle of attack was considered. Additionally, the number of altitudes at which radio-frequency blackout was predicted in the numerical simulations declined when using the three-dimensional model for considering the angle of attack.
  • Yusuke Takahashi, Reo Nakasato, Nobuyuki Oshima
    Aerospace 3 1 2 - 2 2016年01月 [査読有り][通常論文]
  • Yusuke Takahashi
    JOURNAL OF PHYSICS D-APPLIED PHYSICS 49 1 015201  2016年01月 [査読有り][通常論文]
     
    An analysis model of plasma flow and electromagnetic waves around a reentry vehicle for radio frequency blackout prediction during aerodynamic heating was developed in this study. The model was validated based on experimental results from the radio attenuation measurement program. The plasma flow properties, such as electron number density, in the shock layer and wake region were obtained using a newly developed unstructured grid solver that incorporated real gas effect models and could treat thermochemically non-equilibrium flow. To predict the electromagnetic waves in plasma, a frequency-dependent finite-difference time-domain method was used. Moreover, the complicated behaviour of electromagnetic waves in the plasma layer during atmospheric reentry was clarified at several altitudes. The prediction performance of the combined model was evaluated with profiles and peak values of the electron number density in the plasma layer. In addition, to validate the models, the signal losses measured during communication with the reentry vehicle were directly compared with the predicted results. Based on the study, it was suggested that the present analysis model accurately predicts the radio frequency blackout and plasma attenuation of electromagnetic waves in plasma in communication.
  • Yusuke Takahashi, Kazuhiko Yamada, Takashi Abe, Kojiro Suzuki
    JOURNAL OF SPACECRAFT AND ROCKETS 52 6 1530 - 1541 2015年11月 [査読有り][通常論文]
     
    A demonstration flight of an advanced reentry vehicle was carried out using a sounding rocket. The vehicle was equipped with a flexible (membrane) aeroshell deployed by an inflatable torus structure. Its most remarkable feature was the low ballistic coefficient that enables reduction in aerodynamic heating and deceleration at a high altitude. During the suborbital reentry, temperatures at several locations on a backside of the flexible aeroshell and inside the capsule were measured by means of embedded thermocouples. The aerodynamic heating behavior of the vehicle was investigated using the measured temperature history, in combination with a numerical prediction in which a flow-field simulation of the heating was conducted. In this flow-field simulation, both laminar flow and turbulent flow were assumed, and the deformation of the flexible aeroshell was considered. A thermal model of the capsule and membrane aeroshell was developed, and the heat flux profiles of the vehicle surface during aerodynamic heating were constructed based on the measured temperatures. The measured temperature data were found to be in reasonable agreement with the predicted data if the flow field near the capsule of the vehicle was assumed to be laminar, with a transition to turbulent flow near the membrane aeroshell.
  • Yu Minghao, Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe, Kazuhiko Yamada, Takashi Abe, Satoshi Miyatani
    PLASMA SCIENCE & TECHNOLOGY 17 9 749 - 760 2015年09月 [査読有り][通常論文]
     
    Two-dimensional (2D) numerical simulations of thermochemical nonequilibrium inductively coupled plasma (ICP) flows inside a 10-kW inductively coupled plasma wind tunnel (ICPWT) were carried out with nitrogen as the working gas. Compressible axisymmetric NavierStokes (N-S) equations coupled with magnetic vector potential equations were solved. A fourtemperature model including an improved electron-vibration relaxation time was used to model the internal energy exchange between electron and heavy particles. The third-order accuracy electron transport properties (3rd AETP) were applied to the simulations. A hybrid chemical kinetic model was adopted to model the chemical nonequilibrium process. The flow characteristics such as thermal nonequilibrium, inductive discharge, effects of Lorentz force were made clear through the present study. It was clarified that the thermal nonequilibrium model played an important role in properly predicting the temperature field. The prediction accuracy can be improved by applying the 3rd AETP to the simulation for this ICPWT.
  • Minghao Yu, Hisashi Kihara, Ken-ichi Abe, Yusuke Takahashi
    JOURNAL OF THE KOREAN PHYSICAL SOCIETY 66 12 1833 - 1840 2015年06月 [査読有り][通常論文]
     
    A relatively simple method for calculating accurately the third-order electron transport properties of nitrogen and air thermal plasmas is presented. The electron transport properties, such as the electrical conductivity and the electron thermal conductivity, were computed with the best and latest available collision cross-section data in the temperature and pressure ranges of T = 300 - 15000 K and p = 0.01 - 1.0 atm, respectively. The results obtained under the atmospheric pressure condition showed good agreements with the experimental and the high-accuracy theoretical results. The presently-introduced method has good application potential in numerical simulations of nitrogen and air inductively-coupled plasmas.
  • Murase Kagenobu, Oshima Nobuyuki, Takahashi Yusuke
    ASME/JSME/KSME 2015 Joint Fluids Engineering Conference, AJKFluids 2015 1A 2015年 
    This paper focuses on the numerical simulation of Sandia National Laboratories "the piloted methane/air burner flame D." Large Eddy Simulation and 2-scalar flamelet approach are applied for the turbulent and partially premixed combustion field, which is expressed by the LES filtered equations of scalar G for tracking the flame surfaces and mixture fraction of a fuel and an oxidizer. The flamelet data consists of temperature, specific volume and laminar flame speed are calculated by the detail chemical reaction with GRI-Mech 3.0. Two kinds of flamelet data are validated one is "equilibrium flamelet data" calculated by 0-dimensional equilibrium solution based on equilibrium model the other is "diffusion flamelet data" calculated by 1-dimensional counter flow solution based on laminar flamelet model. Consequently, the "diffusion flamelet data" gives better result in this type of combustion field.
  • Reo Nakasato, Yusuke Takahashi, Nobuyuki Oshima
    ASME/JSME/KSME 2015 Joint Fluids Engineering Conference, AJKFluids 2015 1A 2015年 
    When a reentry vehicle enters the planetary atmosphere, a strong shock wave is generated and the strong aerodynamic heating appears. Gas temperature in front of the vehicle exceeds 10,000K and chemical reactions (ionizations and dissociations) occur behind the shock wave. Because the reentry vehicle is damaged by the aerodynamic heating, accurate evaluation of the aerodynamic heating in the high-enthalpy flow is necessary for the design and the development of the vehicle. The communication blackout phenomenon which prevents the propagation of the electromagnetic waves can occur by the characteristics of electrons in the shock layer to absorb and reflect the electromagnetic waves. To estimate the communicationable time and understand the behavior of the electromagnetic waves around the vehicle, the accurate evaluation of the plasma flow around the vehicle is also necessary. In this study, the three-dimensional numerical analysis was conducted to consider an angle of attack by using the analysis software for compressible fluid, RG-FaSTAR which has been developed by JAXA. Moreover, unstructured grids were used to make it easier to generate computational grid around the vehicle with complicated shape. Note that RG-FaSTAR is a version of FaSTAR (FaST Aerodynamic Routine) installing the real gas effect. We reproduced the actual flow field around the Atmospheric Reentry Demonstrator (ARD) which was launched by the European Space Agency (ESA) in 1998 and revealed the aerodynamic heating and plasma flow properties during atmospheric reentry. The computational result showed good agreement with measured pressure coefficient at the stagnation point. In addition, the features of the shock layer and the rear region around ARD were revealed.
  • Dongheun HA, Yusuke TAKAHASHI, Kazuhiko YAMADA, Takashi ABE
    Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan 12 ists29 Po_2_57 - Po_2_62 THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 2014年12月 [査読有り][通常論文]
     
    An inflatable re-entry vehicle is a candidate for future re-entry systems. Owing to the large area and configuration of the vehicle, it can afford a few advantages during the re-entry, descent, and landing approach, such as a decrease of aerodynamic heating and soft landing without requiring a parachute system. To investigate aerodynamic characteristics of inflatable reentry vehicle at low-Mach-number flight, wind tunnel tests were performed in JAXA Low-Speed-Wind tunnel. In this research, we investigated aerodynamic characteristics of 2 types of inflatable reentry vehicle, SMAAC and TITANS, at a low-Mach-number by using numerical simulation. Through the flow field simulation, it was indicated that the computed result of drag coefficient shows reasonable agreement with the experimental one. In the case of TITANS, the computed results showed good agreements compared with experimental results though it was confirmed that a blockage effect was observed.
  • Yusuke Takahashi, Kazuhiko Yamada, Takashi Abe
    JOURNAL OF SPACECRAFT AND ROCKETS 51 6 1954 - 1964 2014年11月 [査読有り][通常論文]
     
    A numerical simulation model that combines the plasma flows and electromagnetic waves around a reentry vehicle during atmospheric reentry was developed to evaluate the radio frequency blackout and plasma attenuation. The physical properties of the plasma flow in the shock layer and wake region were obtained using a computational fluid dynamics technique. The electromagnetic waves were expressed using a frequency-dependent finite difference time domain method with the plasma properties. Combined simulations were performed for the atmospheric reentry demonstrator of the ESA at various altitudes based on reentry orbit data. The electromagnetic wave behaviors around the vehicle during atmospheric reentry were investigated in detail. Moreover, a parametric analysis with different ionization reaction models was performed. It was confirmed that the vehicle is surrounded by the plasma and the propagation of the electromagnetic waves is prevented at high altitude. Then, the plasma is dissipated and the propagation recovers at low altitude. Validation of the simulation model was performed based on the plasma attenuation history of the experimental flight data. A comparison of the measured and predicted results showed good agreement. It was concluded that the combined simulation model could be an effective tool for investigating the radio frequency blackout and the plasma attenuation of radio wave communication.
  • Yu Minghao, Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe, Kazuhiko Yamada, Takashi Abe
    PLASMA SCIENCE & TECHNOLOGY 16 10 930 - 940 2014年10月 [査読有り][通常論文]
     
    Numerical simulations of 10 kW and 110 kW inductively coupled plasma (ICP) wind tunnels were carried out to study physical properties of the flow inside the ICP torch and vacuum chamber with air as the working gas. Two-dimensional compressible axisymmetric NavierStokes (N-S) equations that took into account 11 species and 49 chemical reactions of air, were solved. A heat source model was used to describe the heating phenomenon instead of solving the electromagnetic equations. In the vacuum chamber, a four-temperature model was coupled with N-S equations. Numerical results for the 10 kW ICP wind tunnel are presented and discussed in detail as a representative case. It was found that the plasma flow in the vacuum chamber tended to be in local thermochemical equilibrium. To study the influence of operation conditions on the flow field, simulations were carried out for different chamber pressures and/or input powers. The computational results for the above two ICP wind tunnels were compared with corresponding experimental data. The computational and experimental results agree well, therefore the flow fields of ICP wind tunnels can be clearly understood.
  • Naoya Hirata, Masataka Yamada, Hisashi Kihara, Ken-ichi Abe, Yusuke Takahashi
    Journal of Thermophysics and Heat Trasnfer, 28 4 709 - 803 2014年10月 [査読有り][通常論文]
  • Yusuke Takahashi, Kazuhiko Yamada, Takashi Abe
    JOURNAL OF SPACECRAFT AND ROCKETS 51 2 430 - 441 2014年03月 [査読有り][通常論文]
     
    Numerical simulations of the plasma flow and electromagnetic wave around a membrane-aeroshell type reentry vehicle were performed using various physical model combinations, and the possibility of radio frequency blackout of transceiver antenna embedded at the rear of the vehicle was investigated. The flowfield was assumed to be in thermochemical nonequilibrium, and it was described by the Navier-Stokes equations with a multitemperature model and the equation of state. The simulations were performed for several altitudes, including the highest heat flux point according to reentry orbit data. Through these computations, the detailed distributions of the flowfield properties in the shock layer and wake region were successfully obtained. To evaluate the possibility of radio frequency blackout during atmospheric reentry, the distribution of the electron number density around the inflatable vehicle was clarified. A frequency-dependent finite-difference time-domain method was used for simulations of electromagnetic waves, and the physical properties were obtained from the computational results of the plasma flow calculation. Electromagnetic wave behaviors in an ionized gas region behind the inflatable vehicle were investigated. It was found that the number density of electrons was sufficiently small and that the electromagnetic waves can propagate with no reflection and less attenuation. These results suggest that radio frequency blackout may not occur during the atmospheric reentry of the inflatable vehicle.
  • Yusuke Takahashi, Takashi Abe, Hiroki Takayanagi, Masahito Mizuno, Hisashi Kihara, Ken-ichi Abe
    JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER 28 1 9 - 17 2014年01月 [査読有り][通常論文]
     
    Turbulent plasma flows in arc heaters, such as Japan Aerospace Exploration Agency's 750 kW, NASA's 20 MW, and Kyushu University's 20 kW facilities, were investigated, and the distributions of the flowfield properties were successfully obtained. The arc discharge in the constrictor section and the expansion processes in the nozzle section played key roles in the formation of an arc-heated flow. Hence, for accurately predicting high-enthalpy flow properties, it was important to correctly model the complex phenomena observed in various-scale facilities. For this purpose, an integrated analysis model to simulate various-scale arc-heated flows with high accuracy was developed. The turbulent flowfield was described using the Reynolds-averaged Navier-Stokes equations with a multitemperature model, which was tightly coupled with electric-field and radiation-field calculations. A sophisticated and low-cost radiation model and a low-Reynolds-number two-equation turbulence model were introduced into the flowfield simulation. To validate the present integrated analysis model, the computed results were compared with the corresponding experimental data for the mass-averaged enthalpy, the translational and rotational temperatures, and the number density of nitrogen obtained through spectroscopic and laser-induced fluorescence techniques. Moreover, the mechanisms of energy input by discharge and energy loss are discussed, along with the distributions of the electronic excitation temperature and heat flux on the constrictor wall derived from the arc column. Although the results indicated that a relatively detailed discharge model is required to describe the arc discharge with relatively high accuracy, the present flowfield model was generally in good agreement with various operating conditions of the facilities.
  • Dongheun Ha, Yusuke Takahashi, Kazuhiko Yamada, Takashi Abe
    32nd AIAA Applied Aerodynamics Conference 2014年 
    A flight experiment of an inatable reentry vehicle, which equips a thin membrane aeroshell deployed by an inatable torus structure, was performed by a JAXA S-310-41 sounding rocket. The vehicle successfully demonstrated deceleration at a high altitude. During the reentry ight, position, velocity and acceleration of the vehicle were obtained by the global positioning system. Moreover, drag coefficient history was evaluated by the acceleration of vehicle with atmospheric density and temperature by a global reference atmospheric model. Experimental drag coefficient was almost constant value of 1.5 in supersonic region, while that decreased to 1.0 in subsonic region. At transonic region, steep decrease of the drag coefficient was confirmed. To study detailed aerodynamics for the reentry vehicle, flow field simulations were conducted with computational uid dynamics techniques. Aerodynamic force acting on the vehicle was investigated with the measured data throughout the supersonic and subsonic regions. In theflow field simulation, it was indicated that the computed result of drag coefficient shows reasonable agreement with the experimental one. In addition, it was clarified that compressible effect in front of the vehicle remarkably appears in supersonic region, and a feature of vortex ring at the rear of the vehicle is formed in subsonic region.
  • Yusuke Takahashi, Nobuyuki Oshima, Yasunori Iwai
    11TH WORLD CONGRESS ON COMPUTATIONAL MECHANICS; 5TH EUROPEAN CONFERENCE ON COMPUTATIONAL MECHANICS; 6TH EUROPEAN CONFERENCE ON COMPUTATIONAL FLUID DYNAMICS, VOLS V - VI 5792 - 5803 2014年 
    Combustion flow field in an industrial gas-turbine combustor was numerically investigated with a newly-developed turbulent combustion model. For turbulent model, large-eddy simulation technique was introduced to simulate unsteady phenomena in detail. The combustion model was based on a two-scalar flamelet approach coupling the two concepts of premixed and non-premixed flames expressed by the conservative scalar of mixture fraction and the levelset function of premixed flame surface, respectively. A fine full tetra computational mesh of 45.5 million cells and 7.7 million nodes was used to resolve turbulent fluctuation with high accuracy in the combustion field. The simulations were performed for two calculation conditions reproducing diffusion-like and premixed-like flames and for three conditions decreasing fuel inlet to investigate flame extinction behavior. It was indicated that premixed or partial premixed turbulent flames by complex burner system in the real scale combustor can be reasonably captured by the present simulation model.
  • Minghao Yu, Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe, Kazuhiko Yamada, Takashi Abe
    PROCEEDINGS OF THE 29TH INTERNATIONAL SYMPOSIUM ON RAREFIED GAS DYNAMICS 1628 1124 - 1131 2014年 [査読有り][通常論文]
     
    Numerical investigation of nonequilibrium inductively coupled plasma (ICP) flow was carried out to study the physical properties of the flow inside a 10-kW ICP torch with the working gas being nitrogen. The flow field was described by two-dimensional compressible axisymmetric Navier-Stokes (N-S) equations that took into account 5 species and 8 chemical reactions. The magnetic vector-potential equations were tightly coupled with the flow-field equations to describe the heating process by inductive discharge. A four-temperature model was adopted to model thermal nonequilibrium process in the discharge torch. The characteristics of ICP flow such as thermal nonequilibrium, inductive discharge, and strong effects of Lorentz forces became clear through the present study.
  • Takanori Akahori, Katsumi Hiraoka, Yusuke Takahashi, Yasunori Nagata, Kazuhiko Yamada, Takashi Abe
    51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 2013 2013年 
    FLow generated in the expansion tube was numerically simulated to evaluate the test flow conditions including the test flow period. For this purpose, the chemically equilibrium flow is assumed and the boundary layer effect is considered. To identify the start of the test flow period, the contact surface is intentionally detected. The boundary layer generated from the foot of the propagating shock wave was found to significantly modify the flow structure and thus the test flow conditions. The modification of the flow structure due to the tapered nozzle was clarified. Some of the numerical results are validated with the respective experimental measurement. In summary, the test flow conditions and the test flow period were estimated. © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
  • Yusuke Takahashi, Kazuhiko Yamada, Takashi Abe, Kojiro Suzuki
    AIAA Aerodynamic Decelerator Systems (ADS) Conference 2013 2013年 [査読有り][通常論文]
     
    A reentry flight demonstration of an advanced reentry vehicle was carried out using a sounding rocket. The vehicle is equipped with a flexible (membrane) aeroshell deployed by an inflatable torus structure. During the reentry flight, temperatures at several locations of a backside of a flexible aeroshell and a sidewall of a capsule were measured by means of embedded thermocouples. Behavior of aerodynamic heating of the vehicle is investigated along with the measured temperature history, combining the numerical prediction in which the numerical flow simulation and the heating estimation based on it were conducted. In the flow field simulation, not only laminar flow but also turbulent flow were assumed, and modification of the flexible aero-shell were considered. It was found that the measured temperature data shows a reasonable agreement with the predicted one if the flow field near the membrane aeroshell of the vehicle is assumed to be turbulent flow. © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
  • Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe
    JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER 26 3 540 - 544 2012年07月 [査読有り][通常論文]
  • Yusuke Takahashi, Yusuke Takahashi, Takashi Abe, Takashi Abe, Hiroki Takayanagi, Hiroki Takayanagi, Masahito Mizuno, Masahito Mizuno, Hisashi Kihara, Hisashi Kihara, Ken Ichi Abe, Ken Ichi Abe
    50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition 2012年06月20日 [査読有り][通常論文]
     
    Turbulent plasma flows in arc heaters such as JAXA 750 kW, NASA 20 MW and Kyushu University 20 kW facilities were investigated and the distributions of flow-field properties were successfully obtained. For this purpose, an integrated analysis model to simulate various-scale arc-heated flows with high accuracy was developed. The turbulent flow field was described by the Navier-Stokes equations with a multitemperature model, which was tightly coupled with electric-field and radiation-field calculations. An accurate and low-cost radiation model and a low-Reynolds number two-equation turbulence model were introduced into the flow-field simulation. Arc discharge in constrictor section and expansion processes in nozzle section play key roles for forming an arc-heated flow. Thus, it is important to correctly model those phenomena for predicting the high-enthalpy flow properties accurately. To validate the present numerical model, the computed results were compared with the corresponding experimental data for the mass-averaged enthalpy, temperatures and number density. Through the comparison of the predicted results with detailed experimental data obtained by spectroscopic and laser-induced fluorescence techniques, the present integrated analysis model was validated. In addition, the mechanisms of energy input by discharge and energy loss were discussed with distributions of the temperature and heat flux derived from the arc column. Although it was indicated that more detailed discharge model is possibly required in order to describe arc discharge with higher accuracy, the present flow-field model was found to give generally good agreement for various operating conditions of the facilities. © 2012 by the American Institute of Aeronautics and Astronautics, Inc.
  • N. Hirata, S. Nozawa, Y. Takahashi, H. Kihara, K. Abe
    Computational Thermal Sciences 4 3 225 - 242 2012年 [査読有り][通常論文]
     
    A numerical simulation of a lightweight ablator in an arc-heated flow was carried out. Thermal response analysis of the ablator was coupled with thermochemical nonequilibrium analysis of an arc jet around the ablator. In the thermal response analysis, the pyrolysis gas flow inside the ablator was calculated in detail by solving the conservation equations. Phenomena such as heat conduction, pyrolysis of resin, surface reactions, and recession were also considered in the simulation. Furthermore, in order to evaluate the injection of the ablation gas (pyrolysis gas and carbonaceous gas generated by the surface reactions) from the ablator surface into the outer flow field, a computational fluid dynamics code was extended by including further chemical species besides those in the previous study. This also allowed the simulations for wider-range flow conditions such as a nitrogen flow and airflow. The simulation was conducted for flow conditions of a 20 kW arc-heated nitrogen flow and a 750 kW arc-heated airflow. The results from the former simulation were compared with the experimental data and the computational results using other models. This comparison showed that the effect of the pyrolysis gas flow on the thermal response was significant, and thus the detailed analysis considering the multidimensional pyrolysis gas flow led to a considerable improvement of the predictive performance. © 2012 by Begell House, Inc.
  • Yusuke Takahashi, Kazuhiko Yamada, Takashi Abe
    42nd AIAA Fluid Dynamics Conference and Exhibit 2012 2012年 
    Numerical simulations of a plasma flow around a membrane-aeroshell type reentry vehicle with various physical models combination were performed and radio frequency blackout for transceiver antenna embedded at the rear of the vehicle was investigated. The flow field was assumed to be thermochemical nonequilibrium and was described by the Navier-Stokes equations with a multitemperature model and the equation of state. The simulations were performed for several altitudes including the highest heat flux point according to a reentry orbit data. Through these computations, flow-field properties distributions in shock layer and wake region were successfully obtained in detail. In order to evaluate the radio frequency blackout during atmospheric reentry, distribution of electron number density around the inflatable vehicle were clarified and the RF blackout possibility was discussed. In addition, simulations of electromagnetic waves based on the computational results of the plasma flow calculation were performed with a frequency-dependent finite-difference time-domain method. Electromagnetic wave behaviors in an ionized-gas region behind the inflatable vehicle were investigated. It was seen that the number density of electrons was sufficiently small and the electromagnetic waves can propagate with less reflection and attenuation. From these reasons, we found that the RF blackout hardly occurs during atmospheric reentry. © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
  • Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe
    JOURNAL OF PHYSICS D-APPLIED PHYSICS 44 8 085203  2011年03月 [査読有り][通常論文]
     
    Turbulent plasma flow in large-scale arc heaters such as JAXA 750 kW and NASA 20 MW facilities was investigated and distributions of flow-field properties were successfully obtained. The turbulent flow field was described by the Navier-Stokes equations with a multitemperature model, which was tightly coupled with electric-field and radiation-field calculations. An accurate and low-cost radiation model, and a low Reynolds number two-equation turbulence model were introduced into the flow-field simulation. It was confirmed that the plasma flows in the arc-heating facilities were in a highly thermochemical nonequilibrium state in the expansion section and that the arc discharge plays a critical role in the heating section. It was quantitatively clarified that radiation and turbulence phenomena were very important in transferring heat and momentum from the high-temperature flow near the core to the cold gas region near the facility wall. To confirm the effectiveness of the present numerical model, the obtained results were compared with experimental data for the arc voltage, mass-averaged enthalpy, chamber pressure and heat efficiency. The present flow-field model was found to give good agreement for various operating conditions of the facilities.
  • Yusuke Takahashi, Hisashi Kihara, Ken Ichi Abe
    27th Congress of the International Council of the Aeronautical Sciences 2010, ICAS 2010 2 1470 - 1479 2010年12月01日 [査読有り][通常論文]
     
    Turbulent plasma flow in large-scale arc heater such as NASA 60 MW Interaction Heating Facility was numerically investigated and the distribution of the arc-heated flow-field properties were successfully obtained.The turbulent flow-field was described by the Reynolds- Averaged Navier-Stokes equations with a multitemperature model,tightly coupled with the electric field and the radiation-field calculations. In addition,an accurate and low-cost radiation model and a low-Reynolds number two-equation turbulence model were introduced into the flowfield simulation.It was quantitatively clarified that radiation and turbulence phenomena are very important mechanisms to transfer heat and momentum from high-temperature core region to cold gas region near the wall.To validate the present numerical model,the numerical solutions were compared with the experimental data,e.g.,arc voltage,mass-averaged enthalpy,chamber pressure and heat efficiency.It was indicated that the present flow-field simulation model showed good agreement over various operating conditions of the facilities. © 2010 by the International Council of Aeronautical Sciences - ICAS.
  • Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe
    JOURNAL OF PHYSICS D-APPLIED PHYSICS 43 18 185201  2010年05月 [査読有り][通常論文]
     
    Numerical simulation of a 20 kW constrictor-type arc-heated flow was carried out, and the distribution of the nonequilibrium flow-field properties was obtained. The flow field was described by the Navier-Stokes equations with a multi-temperature model, tightly coupled with the electric-field and radiation-field calculations. As a radiation model, an accurate and low-cost model was introduced into the flow-field simulation. It was confirmed that the plasma flow inside the arc-heated facility is in a state of high nonequilibrium and the arc discharge plays a critical role. By comparing the computational results with/without the radiation model, it was clarified that the radiation exerts significant effects on the heat transport in the constrictor section. Additionally, to validate the present numerical model, the numerical solutions were compared with the experimental data. It was indicated that the present flow-field simulation with a radiation model tends to be in good agreement with the corresponding experimental data.
  • Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe
    JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER 24 1 31 - 39 2010年01月 [査読有り][通常論文]
     
    Numerical simulations are carried out and the distributions of flowfield properties are obtained for nonequilibrium, flows in a 20 kW constrictor-type and a 750 kW segmented-type arc-heated wind tunnel. In these arc heaters, it is confirmed that each plasma flow is highly in nonequilibrium and are discharge plays critical roles. The flowfield is described by the Navier-Stokes equations with a multitemperature model. To validate the present numerical model, the numerical solutions are compared with the corresponding experimental data. The flow characteristics in the 20 and 750 kW arc heaters (e.g., the arc discharge and the supersonic expansion) become clear through the present simulations. In particular, the computed results for the 20 kW arc heater indicate almost full dissociation/ionization reactions and thermochemical equilibrium in the constrictor section, while strong nonequilibrium clearly appears in the nozzle section.
  • Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe
    RAREFIED GAS DYNAMICS 1084 883 - 888 2009年 [査読無し][通常論文]
     
    Numerical simulation is carried out and the distribution of flow field properties is obtained for nonequilibrium flow in a constrictor-type 20kW arc-heated wind tunnel. In the arc heater, plasma flow is highly in nonequilibrium and arc discharge plays a critical role. The flow field is described by the Navier-Stokes equations with a multi-temperature model. The flow field equations are solved with the governing equation for the electric field being coupled. Furthermore, to validate the present numerical model, the numerical solutions are compared with the corresponding experimental data. The flow characteristics in the 20kW arc heater, e.g., the arc charge and the supersonic expansion, become clear through the present simulation. Moreover, the computed results for the arc heater indicate almost full dissociation/ionization reactions and thermochemical equilibrium in the constrictor part, while strong nonequilibrium clearly appears in the nozzle section.

MISC

書籍等出版物

  • Encyclopedia of Plasma Technology
    Yusuke Takahashi (担当:分担執筆範囲:Arc-Heated Wind Tunnel)
    CRC Press, Taylor & Francis Group 2017年02月 (ISBN: 146650059X) 1728

講演・口頭発表等

  • Study on Mitigation of Reentry Blackout by Surface Catalysis Effects in Arc-Heated Wind Tunnel  [通常講演]
    Hideto Takasawa, Yusuke Takahashi, Nobuyuki Oshima, Hisashi Kihara
    Aerospace Europe Conference 2020, 2020年02月 口頭発表（一般） Bordeaux
  • 再突入ブラックアウト低減化に向けた数値的研究  [招待講演]
    高橋裕介
    日本学術会議第9回計算力学シンポジウム 2019年12月 口頭発表（招待・特別）
  • Toru TSURUMOTO, Yusuke TAKAHASHI, Hiroshi TERASHIMA, Nobuyuki OSHIMA
    8TH EUROPEAN CONFERENCE FOR AERONAUTICS AND SPACE SCIENCES (EUCASS) 2019年07月 口頭発表（一般） Madrid
  • Aerodynamics of Inflatable Nano-Satellite “EGG” in Low Earth Orbit and Reentry Duration  [通常講演]
    Naoya Enoki, Yusuke Takahashi, Nobuyuki Oshima, Kazuhiko Yamada, Kojiro Suzuki
    31st Internal Symposium on Rarefied Gas Dynamics 2018年07月 口頭発表（一般）
  • 大気再突入時における宇宙機の空力・空力加熱について  [招待講演]
    高橋裕介, 小池太輝
    北海道大学-JAXA連携企画講演会・HASTIC学術技術講演会 2018年03月 口頭発表（招待・特別）
  • Taiki Koike, Yusuke Takahashi, Nobuyuki Oshima, Kazuhiko Yamada
    AIAA Atmospheric Flight Mechanics Conference, 2018 2018年 American Institute of Aeronautics and Astronautics Inc, AIAA
     
    Aerodynamic heating around a flare-type membrane inflatable vehicle during Earth atmospheric reentry was investigated using numerical simulation approach. This vehicle, which is mainly composed of the capsule, membrane aeroshell and inflatable torus, has been developed by the Membrane Aeroshell for Atmospheric-entry Capsule (MAAC) group as a one of the innovative reentry systems. Analysis solver for reentry flows around the vehicle was RG-FaSTAR, which is a branch version of JAXA fast aerodynamic routine (FaSTAR). In addition, structure analysis solver also was used for membrane deformation in a loosely-coupled manner with the flow field. In the present research, the effects of angle of attack (AoA) and membrane aeroshell deformation on aerodynamic heating were investigated. The numerical results showed that heat flux distribution drastically varies with the increase in AoA because of changes of flow field, and heat flux value at the stagnation point for case of AoA of 40 degree was 3.09 times as high as that for 0 degree. Moreover, the deformed shapes for case of AoA of 0 and 40 degrees were calculated in the way which the pressure distributions obtained using initial (undeformed) shape were given as the aerodynamic force. The difference of heat fluxes between the deformed and initial shapes on the head capsule part was remarkable as 188.8% for case of AoA of 0 degree. On the other hand, it was indicated that membrane deformation for case of AoA of 40 degree insignificantly affects the peak heat flux value on the inflatable torus such as the case of the AoA of 0 degree.
  • Aerodynamic Heating Prediction of Flare-type Membrane Inflatable Reentry Vehicle from Low Earth Orbit  [通常講演]
    Taiki Koike, Yusuke Takahashi, Nobuyuki Oshima, Kazuhiko Yamada
    2018 AIAA Atmospheric Flight Mechanics Conference, AIAA SciTech Forum 2018年01月 口頭発表（一般）
  • Aerodynamic Instability of Flare-type Membrane Inflatable Vehicle in Suborbital Reentry Demonstration  [通常講演]
    Tatsushi OHASHI, Manabu MATSUNAGA, Yusuke TAKAHASHI, Hiroshi TERASHIMA, Nobuyuki OSHIMA
    The Ninth JSME-KSME Thermal and Fluids Engineering Conference (TFEC9) 2017年10月 口頭発表（一般）
  • Prediction of electromagnetic waves around an inflatable reentry vehicle in an atmospheric reentry mission  [通常講演]
    Naoya ENOKI, Manabu MATSUNAGA, Yusuke TAKAHASHI, Hiroshi TERASHIMA, Nobuyuki OSHIMA, Kazuhiko YAMADA, Kojiro SUZUKI
    The Ninth JSME-KSME Thermal and Fluids Engineering Conference (TFEC9) 2017年10月 口頭発表（一般）
  • Large-Eddy Simulation with a New Flamelet Model for Partially Premixed Combustion in a Gas-Turbine Combustor  [通常講演]
    Keisuke Tanaka, Tomonari Sato, Nobuyuki Oshima, Jiun Kim, Yusuke Takahashi, Yasunori Iwai
    the ASME 2017 Power and Energy Conference 2017年06月 口頭発表（一般）
  • Numerical Simulation of Plasma Flows and Radio-Frequency Blackout in Atmospheric Reentry Demonstrator Mission  [通常講演]
    Minseok Jung, Hisashi Kihara, Ken-ichi Abe, Yusuke Takahashi
    47th AIAA Fluid Dynamics Conference, AIAA AVIATION Forum 2017年06月 口頭発表（一般）
  • Aerodynamic Heating Prediction of an Inflatable Reentry Vehicle in a Hypersonic Wind Tunnel  [通常講演]
    Manabu Matsunaga, Yusuke Takahashi, Nobuyuki Oshima, Kazuhiko Yamada
    55th AIAA Aerospace Sciences Meeting 2017年01月 口頭発表（一般）
  • Manabu Matsunaga, Yusuke Takahashi, Nobuyuki Oshima, Kazuhiko Yamada
    AIAA SciTech Forum - 55th AIAA Aerospace Sciences Meeting 2017年 American Institute of Aeronautics and Astronautics Inc.
     
    Aerodynamic heating around an inflatable reentry vehicle was investigated using hypersonic wind tunnel and numerical approach. The inflatable reentry vehicle is mainly composed of the capsule, membrane aeroshell (rigid in the wind tunnel), and inflatable torus. Basic configuration of the reentry vehicle (HWT-MAAC) is a scaled-down model of SMAAC, which was used in demonstration mission with JAXA / ISAS S-310-41 sounding rocket. Spherical cap of the SMAAC model was replaced by blunt top. Freestream condition of Mach number of 10, reservoir pressure of 2.5 MPa, and reservoir temperature of 950 K was used in the hypersonic wind tunnel test. Heat flux distribution on the surface and density gradient around the HWT-MAAC were measured by infrared thermography and Schliren photograph techniques, respectively. It was found that heat flux distribution widely varies according to angle of attack of the vehicle and a recirculation region near the membrane aeroshell section of the vehicle can appear at high angle of attack. Flow field was also numerically simulated with computational fluid dynamics approach. Analysis solver used here in was RG-FaSTAR, which is a version of JAXA fast aerodynamic routine (FaSTAR). Structures of shock layer and expansion region around HWT-MAAC was discussed through the analysis approach and the wind tunnel results.
  • NUMERICAL INVESTIGATION OF ABLATION EFFECT ON AERODYNAMIC HEATING FOR HIGH VELOCITY REENTRY CAPSULE  [通常講演]
    Manabu Matsunaga, Takahiro Sasaki, Yusuke Takahashi, Nobuyuki Oshima
    The 27th International Symposium on Transport Phenomena (ISTP27) 2016年09月 口頭発表（一般）
  • NUMERICAL ANALYSIS OF RADIO FREQUENCY BLACKOUT FOR ATMOSPHERIC REENTRY VEHICLE USING CFD-CEM COMBINED METHOD  [通常講演]
    Yusuke Takahashi, Reo Nakasato, Nobuyuki Oshima
    VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016) 2016年06月 口頭発表（一般） Crete Island, Greece
  • Yusuke Takahashi, Reo Nakasato, Nobuyuki Oshima
    ECCOMAS Congress 2016 - Proceedings of the 7th European Congress on Computational Methods in Applied Sciences and Engineering 2016年 National Technical University of Athens
     
    Numerical simulations of electromagnetic waves around the atmospheric reentry demonstrator (ARD) of the European Space Agency (ESA) in an atmospheric reentry mission were conducted with a combined method of computational fluid dynamics (CFD) and computational electromagnetics (CEM). During the reentry mission, radio frequency blackout and plasma attenuation of radio waves in communications with a data-relay satellite were observed. Cut-off of waves propagation was caused by highly dense plasma formed by a strong shock wave formed in front of the vehicle due to orbital speed. In this study, the physical properties of the plasma flow in the shock layer and wake region of the ESA ARD were obtained using a high-enthalpy flow solver applicable unstructured grids. Moreover, electromagnetic waves were calculated using a frequency-dependent finite-difference time-domain method using the plasma properties. The present analysis model was validated based on experimental flight data of ESA ARD. Comparisons of the measured and predicted results showed good agreements. Attenuation and reflection by reentry plasma were clarified in detail using the present model. It was suggested that the analysis model could be an effective tool for investigating radio frequency blackout and plasma attenuation in radio wave communication. Behaviors of plasma and electromagnetic waves around ESA ARD for several altitudes were investigated using the proposed model in detail.
  • Development of Analysis Tools for Space Vehicle in Atmospheric Reentry Mission  [招待講演]
    Yusuke Takahashi, Nobuyuki Oshima
    Korea-Japan CFD Workshop 2015 2015年12月 口頭発表（招待・特別）
  • Numerical Investigation of Turbulent Combustion Flow in Industrial Combustor with Flamelet Approach  [通常講演]
    Tenshi Sasaki, Yusuke Takahashi, Nobuyuki Oshima, Yasunori Iwai
    International Conference on Power Engineering-15 (ICOPE-15) 2015年11月 口頭発表（一般） Yokohama, Japan
  • Accuracy Verification of the Turbulent Flame LES Model by a Methane/Air Burner Flame  [通常講演]
    Kagenobu Murase, Nobuyuki Oshima, Yusuke Takahashi
    ASME-JSME-KSME Joint Fluids Engineering Conference 2015 2015年07月 口頭発表（一般） Seoul, Korea
  • Aerodynamic Simulation of Closed-Canopy-Type Parafoil for Martian Exploration Mission  [通常講演]
    Daiki Harada, Yusuke Takahashi, Nobuyuki Oshima, Kazuhiko Yamada
    ASME-JSME-KSME Joint Fluids Engineering Conference 2015 2015年07月 口頭発表（一般） Seoul, Korea
  • Numerical Study of Plasma Flow around a Reentry Vehicle during Atmospheric Reentry with an Unstructured Grid Solver  [通常講演]
    Reo Nakasato, Yusuke Takahashi, Nobuyuki Oshima
    ASME-JSME-KSME Joint Fluids Engineering Conference 2015 2015年07月 口頭発表（一般） Seoul, Korea
  • Large-Eddy Simulation of Transient Behavior in a Combustion Field for Gas-Turbine Engine  [通常講演]
    Yusuke Takahashi, Nobuyuki Oshima, Yasunori Iwai
    WCCM XI-ECCM V-ECFD VI 2014年07月 口頭発表（一般）
  • Numerical Simulation of Flow Field around an Inflatable Vehicle during a Reentry Demonstration Flight  [通常講演]
    Dongheun Ha, Yusuke Takahashi, Kazuhiko Yamada, Takashi Abe
    AIAA-2014-3283 2014年06月 口頭発表（一般）
  • Numerical Investigation of Flow Fields in Inductively Coupled Plasma Wind Tunnel  [通常講演]
    Minghao Yu, Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe, Kazuhiko Yamada, Takashi Abe
    4th Asian Symposium on Computational Heat Transfer and Fluid Flow 2013年06月 口頭発表（一般）
  • Aerodynamic Simulation of an Inflatable Re-Entry Vehicle Performance in Low Speed Wind Tunnel  [通常講演]
    Dongheun Ha, Yusuke Takahashi, Kazuhiko Yamada, Takashi Abe
    29th International Symposium on Space Technology and Science 2013年06月 口頭発表（一般）
  • Aerodynamic Heating around an Inflatable Vehicle during a Reentry Demonstration Flight by a Sounding Rocket  [通常講演]
    Yusuke Takahashi, Kazuhiko Yamada, Takashi Abe, Kojiro Suzuki
    AIAA-2013-1303 2013年03月 口頭発表（一般）
  • Numerical Evaluation of Nonequilibrium Plasma Flow in 1kW Class Arc Thruster  [通常講演]
    Minghao YU, Yusuke TAKAHASHI, Ken-ichi ABE, Hisashi KIHARA
    5th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials 2013年01月 ポスター発表
  • Numerical Prediction of Test Flow Conditions for Low Density High Enthalpy Flow in an Expansion Tube Facility  [通常講演]
    Takanori Akahori, Katsumi Haraoka, Yusuke Takahashi, Yasunori Nagata, Kazuhiko Yamada, Takashi Abe
    AIAA-2013-1005 2013年01月 口頭発表（一般）
  • Validation of the Scale Effect for the Electrodynamic Interaction of a Magnetized Body in a Weakly-ionized Flow  [通常講演]
    Morimasa Hattori, Aseu Tezuka, Hitoshi Makino, Yasunori Nagata, Yusuke Takahashi, Takashi Abe
    AIAA-2012-2738 2012年06月 口頭発表（一般）
  • Radio Frequency Blackout Possibility for an Inflatable Reentry Vehicle  [通常講演]
    Yusuke Takahashi, Kazuhiko Yamada, Takashi Abe
    AIAA-2012-3110 2012年06月 口頭発表（一般）
  • Nonequilibrium Plasma Flow Properties in Arc-Heated Wind Tunnels  [通常講演]
    Yusuke Takahashi, Takashi Abe, Hiroki Takayanagi, Masahito Mizuno, Hisashi Kihara, Ken-ichi Abe
    AIAA-2012-1240 2012年01月 口頭発表（一般）
  • Numerical Study of Pyrolysis Gas Flow and Heat Transfer inside an Ablator  [通常講演]
    Naoya Hirata, Sohei Nozawa, Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe
    the Asian Symposium on Computational Heat Transfer and Fluid Flow 2011年09月
  • Numerical Simulation of Flow Field and Heat Transfer around HAYABUSA Reentry Capsule  [通常講演]
    Masataka Yamada, Yohei Matsuda, Naoya Hirata, Sohei Nozawa, Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe
    the 28th International Symposium on Space Technology and Science 2011年06月 口頭発表（一般）
  • Numerical Simulation of Flow Fields in Large-Scale Segmented-Type Arc Heaters  [通常講演]
    Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe
    27th Congress of the International Council of the Aeronautical Sciences 2010年09月 口頭発表（一般）
  • Numerical Investigation of Thermal Response of Ablator Exposed to Thermochemical Nonequilibrium Flow’  [通常講演]
    Tadashi Kanzaka, Sohey Nozawa, Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe
    The 6th Asian-Pacific Conference on Aerospace Technology and Science 2009年11月 口頭発表（一般）
  • Numerical Investigation of Thermochemical Nonequilibrium Flow Field in a 20kW Arc Heater Coupled with Electric Field Calculation  [通常講演]
    Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe
    26th International Symposium on Rarefied Gas Dynamics 2008年07月 口頭発表（一般）
  • Numerical Simulation of Plasma Flows in a 20kW Arc-Heated Wind Tunnel Using Multi-Temperature Model  [通常講演]
    Yusuke Takahashi, Hisashi Kihara, Ken-ichi Abe
    Third Asian-Pacific Congress on Computational Mechanics in conjunction with Eleventh International Conference on Enhancement and Promotion of Computational Methods in Engineering and Science (APCOM’07-EPMESC XI) 2007年12月 口頭発表（一般）

担当経験のある科目（授業）

  • Introduction to Flight Dynamics北海道大学大学院
  • Advanced Fluid Engineering北海道大学大学院
  • Computational Fluid Mechanics北海道大学大学院
  • 応用数学演習北海道大学
  • 熱流体力学演習北海道大学
  • Scientific mission and design of reentry spacecraftHokkaido University

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2020年04月 -2023年03月 
    代表者 : 山田 和彦, 永田 靖典, 高橋 裕介, 佐藤 泰貴
     
    本研究課題は、新しい大気圏突入技術として注目されている展開型柔軟エアロシェル技術をさらに進化させて、新たな応用範囲を切り開くことを目的としている。特に、１）大気圏突入中に展開エアロシェルを切り離すことで、探査機を惑星周回軌道投入を実現できる抗力変調型のエアロキャプチャ技術と、２）超軽量で、シンプルかつロバストな展開型エアロシェルが実現できる可能性があるSMA（形状記憶合金）型の展開エアロシェル技術に取り組んでいる。 2021年度の最も重要な成果は2021年12月に実施した極超音速風洞試験である。上記の1),2)の両テーマともに、2020年度に実施した極超音速風洞試験の結果を踏まえて改良した模型や試験システムを用いて、JAXA調布のΦ1.27m極超音速風洞にて風洞試験を実施した。1)の抗力変調型のエアロキャプチャに関しては、６分力測定、及び、画像計測系を改善し、エアロシェル分離時の挙動をより詳細に測定することに成功した。また、エアロシェルサイズを変更した実験を行い、2020年度の成果と併せて、エアロシェル形状の影響についても知見を取得できた。2)のSMA型エアロシェルについては、2020年度の試験時の課題であったフラッタ現象は、模型を改良することで回避でき、極超音速気流中での空力加熱によるSMA型エアロシェルの完全受動展開実験に成功した。展開中の流れ場の可視化、６分力測定、温度履歴の測定を実施し、模型形状と展開挙動の関係や空力特性を取得することができた。 それと平行して、抗力変調型エアロキャプチャに関しては、火星以外の天体（金星）への適用について、軌道解析による評価を行った。また、FSI(Fluid-structure Interaction)解析による柔軟エアロシェルと高速流体の連成解析ツールの構築も進め、これらの現象をより深く理解するための準備を整えた。
  • 数値シミュレーションを用いた大動脈解離及びその治療方法の評価
    一般財団法人 高度情報科学技術研究機構：2022年度 学際大規模情報基盤共同利用・共同研究拠点(JHPCN)公募型共同研究課題
    研究期間 : 2022年04月 -2023年03月 
    代表者 : 武田量, 佐々木克彦, 大島伸行, 横山博一, 黒田明慈, 柴田良一, 高橋裕介, 髙嶋英厳, 李辰宇
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2018年 -2022年 
    代表者 : 高橋 裕介
     
    大気再突入時に高温プラズマに包まれた宇宙機が、地上局やデータ中継衛星との通信途絶現象（通信ブラックアウト）に陥ることがある。通信ブラックアウト低減化は着地着水点の高精度予測や再突入中のデータ送受信の上で重要な課題である。これまで磁場印加や、柔軟構造再突入機、テラヘルツ波など様々な低減化手法が提案されている。いま課題実施者の研究グループでは、表面触媒性を用いた宇宙機後流プラズマ密度低下を利用することによる新しい通信ブラックアウト低減を提案している。ここでは表面効果による通信ブラックアウト低減化メカニズムおよび低減化技術の指針を見出すことを目的とする。 再突入機近傍のプラズマ諸量分布や電磁波挙動の正確な予測が難しく、通信ブラックアウト低減に繋がる知見の探索が困難な状況であった。この問題を緩和するために、再突入時における宇宙機近傍の電磁波挙動を明らかにすることは有効である。本課題実施者は、これまでプラズマ流解析・電磁波解析ソフトウェアを開発し、再突入時における宇宙機近傍の電磁波解析を明らかにしてきた。ここではそれをコア技術として、大型風洞による低減化実証と合わせて研究を推進する。 昨年度に引き続き本年度でもドイツ航空宇宙センター（DLR）に滞在し通信ブラックアウト低減化研究を実施する予定だったが、新型コロナウイルス感染症拡大防止方策に伴う海外移動制限から今年度も残念ながら断念した。一方でDLR研究者との議論は継続しつつ、現所属機関（北海道大学）において遂行可能な低減化研究の実施を行った。それはJAXAプラズマ風洞における実証試験とスーパーコンピューター富岳などを用いた大規模数値計算である。主にはこれら２つのアプローチを用いて従来課題の低減化手法の研究を行うとともに、新しい低減化技術の実験的・数値的実証も実施した。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2017年04月 -2020年03月 
    代表者 : 高橋 裕介
     
    惑星大気再突入時に宇宙機に現れる通信ブラックアウトは高精度着地点予測の妨げや回収コストの増加をもたらすため、その低減化が求められる。本研究では表面触媒効果による通信ブラックアウト低減化技術の可能性を調べ、実験的な実証を行った。アーク加熱風洞と呼ばれる地上において再突入時の高温環境を模擬する装置を用いて再突入プラズマ中の通信状況を再現した。高触媒・低触媒材料の通信模型によって比較試験を行い、高触媒ケースで通信状況が改善される結果を得た。加えて数値解析によってその状況を再現し、低減化に至るメカニズムを明らかにした。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2015年04月 -2018年03月 
    代表者 : 山田 和彦, 永田 靖典, 高橋 裕介, 莊司 泰弘, 鈴木 宏二郎, 今村 宰, 秋田 大輔, 石村 康生, 中篠 恭一
     
    本研究では、超小型衛星に搭載可能な姿勢センサ群を開発し、ISSから放出される超小型衛星EGGを利用し、大気の影響を無視できない超低高度軌道での軽量膜面を有する宇宙機の挙動の実測を行った。超小型衛星EGGの運用において、希薄気体中における軽量な膜面に働く大気抵抗の影響により軌道が変更することを確認するなど、そのダイナミクスを理解するためや解析ツール開発の参照となる貴重な実測データを得ることができた。これらのデータは、運用終了時の衛星を非デブリ化する技術等、将来、超小型衛星にとって重要な技術開発のために役立つと期待される。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2014年04月 -2016年03月 
    代表者 : 高橋 裕介
     
    惑星大気再突入時に宇宙機に現れる通信ブラックアウト・プラズマ減衰予測のための数値解析ソフトウェアを開発した。本ソフトウェアは３次元非構造格子データに対応したもので、対象となる宇宙機の形状再現性および自由度の高い構成となっている。また、過去に再突入試験を実施し通信ブラックアウトや通信電磁波の減衰データが得られているミッションに対して、本ソフトウェアを適用することで解析モデルの検証が行われた。その比較から、本解析モデルが実際的な環境をよく再現することが確認された。本研究によって、宇宙機の通信視野角や通信時間の定量的評価および機体近傍のプラズマ流・電磁波分布を明らかにすることが可能になった。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2011年 -2012年 
    代表者 : 高橋 裕介
     
    高速気流条件においても十分な適用を期待できるプラズマアクチュエータの提案を目標とする.それを進める上でアクチュエータ近傍の流体・放電現象を解明するとともに,物理モデル及び解析モデルの提案を行い,定量的に流れの振る舞いを明らかにすることは性能向上に向けた指針を得る上で重要である.ここではアクチュエータの放電によって誘起されるプラズマ流の解析モデルを開発・提案するとともに,電極近傍でプラズマによって生じる電圧降下モデルを提案した.
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2009年 -2011年 
    代表者 : 高橋 裕介
     
    本研究の目的を,再突入時の高温環境を模擬できるアーク加熱風洞を用いてアブレータ内部現象の定量的な調査を進めるとともに,軽量で耐熱性に優れるアブレータ材料とその形状モデルの指針を見出すことに設定し,本年度における研究を実施した.これまでの成果として,九州大学20kWアーク加熱風洞の加熱部における幅射熱輸送の役割について数値解析を用いて定量的に明らかにした.さらに,JAXA 750kWアーク加熱風洞や,NASA20 MW Aerodynamic Heating Facility,NASA60 MW Interaction Heating Facilityなど,多様な大型アーク加熱風洞に対して,加熱部における乱流・幅射熱輸送の挙動を数値的に調査し,その挙動を明らかにする成果を上げた.ただし,本解析モデルを用いた解析結果は,実験直に比べてアーク電圧を過少予測する傾向にあることがわかった.その理由のひとつとして,電極近傍におけるシースを考慮していなかったことが挙げられる.したがって,アーク加熱風洞の電極近傍におけるシースモデルを提案し,電圧降下及びアーク電圧の評価を行った. また,軽量アブレータが20kW及び750kWアーク加熱気流にさらされる条件下において,内部の熱分解ガス流動を考慮した内部熱応答解析モデルおよび周囲の高温気体との連成解析モデルの構築を行い,アブレータ熱応答解析モデルの高精度化を行った.解析結果と実験結果は良好な一致を示し,より高精度なアブレータ熱応答解析コードが開発された. 本研究を通して開発されたアーク加熱気流解析コード及びアブレータ熱応答解析コードによって,多様な風洞気流の諸量分布を提供することや,アブレータ内部の現象を定量的に調査することが可能になった.したがって,アーク加熱風洞を用いた様々な耐熱材料試験や開発を進める上で,これらは有効なツールになると考えられる.

その他

  • 2021年04月 - 2021年04月  Reviewer Awards (Plasma Science and Technology 2020) 
    https://publishingsupport.iopscience.iop.org/questions/plasma-science-and-technology-2020-reviewer-awards/

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