基本情報
- 所属
- 国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 教授東京大学大学院 教授東京理科大学 理工学研究科機械工学専攻 客員教授
- 学位
- 博士（工学）(2000年3月 東北大学大学院)
- 研究者番号
- 10373440
- J-GLOBAL ID
- 200901044748363926
- researchmap会員ID
- 5000069161
- 外部リンク
宇宙科学航空研究開発機構宇宙科学研究所の大山です．
自分の研究分野にとらわれず，新しい研究分野にも挑戦していきたいと考えています．
自分の研究分野にとらわれず，新しい研究分野にも挑戦していきたいと考えています．
研究キーワード
17研究分野
6経歴
13-
2023年12月 - 現在
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2023年4月 - 現在
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2019年4月 - 現在
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2015年4月 - 2023年11月
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2010年4月 - 2023年3月
学歴
5-
1997年4月 - 2000年3月
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- 2000年
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1995年4月 - 1997年3月
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1991年4月 - 1995年3月
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- 1995年
委員歴
7-
2020年10月 - 現在
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2010年6月 - 現在
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2018年10月 - 2020年9月
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2017年4月 - 2019年3月
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2015年4月 - 2017年3月
受賞
15-
2022年4月
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2021年5月
論文
142-
JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 73(2) 33-41 2025年
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IEEE Access 12 73839-73848 2024年5月 査読有り責任著者
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AIAA SciTech Forum and Exposition, 2024 2024年The Mach number effect on the riblets’ drag reduction performance in turbulent transitional flow regimes is investigated by direct numerical simulations. We focus on the transitional flow occurred by the Tollmien-Schlichting instability. For freestream Mach numbers of 0.2,0.6and 0.85, it is found that the riblets reduce the frictional drag in the turbulent flow region independently of the Mach number, while they tend to increase it in the transitional flow regions. Interestingly, the rate of the drag reduction in the turbulent region decreased with increasing the Mach number. This is because the non-dimensional groove width in the turbulent region changes as the Mach number changes. In other words, the relation between the groove width of the riblets and the size of the longitudinal vortices in the turbulent flow changes as the Mach number changes. The turbulent kinetic energy spectrum in the turbulent region supports these results. The difference in the spectrum between the smooth and riblet surfaces became smaller as the Mach number increased, indicating that the flow structure changes as the Mach number changes. From these results, it is recommended that for high-speed vehicles such as transonic aircraft, riblets be designed in compressible flow rather than incompressible flow.
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AIAA Aviation Forum and ASCEND, 2024 2024年In this study, direct numerical simulations are conducted to reveal the optimal groove width of the riblet at the mainstream Mach number ! = . , the typical cruise speed of a transonic aircraft. Additionally, the study aims to clarify the effect of Mach number on the drag change ratio by comparing it with the incompressible flow condition, ! = . . The results at ! = . show that the lowest drag change ratio, around − %, is observed at " =, and . As for the Mach number effect, the drag change ratio is smaller in the case of ! = . than in the case of ! = . for the same non-dimension groove width ". This is because the drag reduction amount with increasing Mach number is larger on the riblet surface than on the smooth surface since the ejection and sweep intensities on the riblet surface decrease more with increasing Mach number than on the smooth surface. It is also found that the robustness of the drag reduction effect against the change in " is improved for ! = . compared to ! = . .
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進化計算学会論文誌 15(1) 20-30 2024年1月 査読有り責任著者
MISC
65書籍等出版物
1-
Springer Verlag 2009年 RefereedConstraint-handling techniques for evolutionary multiobjective aerodynamic and multidisciplinary designs are focused. Because number of evaluations is strictly limited in aerodynamic or multidisciplinary design optimization due to expensive computational fluid dynamics (CFD) simulations for aerodynamic evaluations, very efficient and robust constraint-handling technique is required for aerodynamic and multidisciplinary design optimizations. First, in Section 2, features of aerodynamic design optimization problems are discussed. Then, in Section 3 constraint-handling techniques used for aerodynamic and multidisciplinary designs are overviewed. Then, an efficient constraint-handling technique suitable to aerodynamic and multidisciplinary designs is introduced with real-world aerodynamic and multidisciplinary applications. Finally, an efficient geometry-constraint-handling technique commonly used for aerodynamic design optimizations is presented. © 2009 Springer-Verlag Berlin Heidelberg.
講演・口頭発表等
399-
IEEE Symposium Series on Computational Intelligence 2021年12月4日
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FAHRZEUG-AERODYNAMIK TAGUNG MIT BEGLEITENDER FACHAUSSTELLUNG 2021年11月23日
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11th International Conference on Evolutionary Multi-Criterion Optimization 2021年3月28日 招待有り
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Accelerating Space Commerce, Exploration, and New Discovery conference, ASCEND 2021 2021年The Japan Aerospace Exploration Agency, in partnership with academia and industry, are developing the Air Turbo Rocket for Innovative Unmanned Mission (ATRIUM) engine: an air turboramjet + rocket combine cycle propulsion system intended to replace conventional liquid rocket engines in Vertical Takeoff Vertical Landing applications, such as reusable sounding rockets. A subscale Flight Test Bed (FTB) vehicle is also being developed to demonstrate the ATRIUM engine in a flight environment. In this paper, the ATRIUM engine and FTB vehicle are introduced, and current progress in their development is summarized. Future test plans and practical applications are also discussed.
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2021 AIAA SCITECH 2021年1月
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AIAA Scitech 2021 Forum 2021年Feedback flow separation control system using the Ape-X DQN-based strategy shows a significant control gain in NACA0015 airfoil with a DBD plasma actuator in deep-stall condition. In the control, the burst-mode actuation with burst frequency of the Strouhal number (F+ ) 6.0 is periodically turned on and off. In this study, the control mechanism of the Ape-X DQN control is investigated using the PIV measurement. The result shows that turn-on of the burst actuation in fully separated flow generates a large spanwise vortex shedding, and it contributes to the suppression of the flow separation. Then the burst actuation with F+ of 6.0 promotes turbulent and the flow attachment is maintained. Although the vortices get smaller gradually and the attached flow cannot maintain, The Ape-X DQN control successfully achieves a significant control gain utilizing the temporal flow separation suppression. .
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COMPSAFE 2020 2020年12月
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大気球シンポジウム: 2020年度 = Balloon Symposium: 2020 2020年11月 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)大気球シンポジウム 2020年度（2020年11月5-6日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)）, 相模原市, 神奈川県著者人数: 12名資料番号: SA6000151030レポート番号: isas20-sbs-030
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Korean Society for Computational Fluids Engineering 25th Conference 2020年10月18日 招待有り
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17th International Conference on Flow Dynamics 2020年10月
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宇宙航空研究開発機構特別資料: 流体力学講演会/航空宇宙数値シミュレーション技術シンポジウム2020オンライン論文集 = JAXA Special Publication: Proceedings of Fluid Dynamics Conference / Aerospace Numerical Simulation Symposium 2020 Online 宇宙航空研究開発機構(JAXA)流体力学講演会/航空宇宙数値シミュレーション技術シンポジウム2020オンライン (2020年9月28日-30日. 日本航空宇宙学会 : 宇宙航空研究開発機構(JAXA)オンライン会議) Fluid Dynamics Conference / Aerospace Numerical Simulation Symposium 2020 Online (September 28-30, 2020. The Japan Society for Aeronautical and Space Sciences : Japan Aerospace Exploration Agency (JAXA), Online meeting) A conceptual study of Mars helicopter for the purpose of observation of the oval tunnels on the Mars has been carried out. Mainly from the limit of the storage size together with the Mars rover, a hexa-rotor drone is proposed with a gross weight of 3 kg. Each rotor consists of 4 blades while the rotor diameter is 460 mm. Optimized design of the airfoil to achieve higher hovering performance is being performed. 形態: カラー図版あり Physical characteristics: Original contains color illustrations 資料番号: AA2030013021 レポート番号: JAXA-SP-20-008
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Genetic and Evolutionary Computation Conference 2020 2020年7月
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2020 AIAA SciTech Forum 2020年1月6日 招待有り
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AIAA Scitech 2020 Forum 2020年This paper experimentally investigates a closed-loop flow separation control system on a NACA 0015 airfoil using a DBD plasma actuator at the chord-Reynolds number of 63,000. The closed-loop control system is constructed utilizing the Deep Reinforcement Learning(DRL). The plasma actuator is installed to the surface of the airfoil at 5% of the chord length from the leading edge and driven with AC voltage. The time series data of surface pressure are used as the input data to the neural network, and the neural network is trained to select the optimum burst frequency of the actuator at angles of attacks of 15 degrees. Ape-X DQN, which is the latest algorithm of DRL is used to improve the training of the neural network. As a result, the neural network is trained stably in Ape-X DQN compared to Deep Q Network (DQN), which is the old algorithm. The result of the time-averaged pressure measurements indicates that the flow controlled by the network trained by Ape-X DQN is suppressed more than the network trained by DQN at angle of attack of 15degrees.
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AIAA Scitech 2020 Forum 2020年1月
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AIAA SCITECH 2021 2020年1月
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AIAA SCITECH 2021 2020年1月
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IEEE Symposium Series on Computational Intelligence 2019年12月
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大気球シンポジウム: 2019年度 = Balloon Symposium: 2019 2019年11月 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)大気球シンポジウム 2019年度（2019年11月7-8日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)）, 相模原市, 神奈川県著者人数: 18名資料番号: SA6000140008レポート番号: isas19-sbs-008
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5th Optimization in Space Engineering Workshop 2019年11月
共同研究・競争的資金等の研究課題
7-
日本学術振興会 科学研究費補助金 2014年4月 - 2017年3月
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日本学術会議 科学研究費補助金 2012年4月 - 2015年3月
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日本学術振興会 科学研究費補助金 2011年4月 - 2013年3月
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日本学術会議 科学研究費補助金 2008年4月 - 2011年3月
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日本学術振興会 科学研究費補助金 2008年4月 - 2010年3月
