研究者業績
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
13-
2022年4月
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2021年5月
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2020年11月
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2020年2月
論文
132-
TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 67(1) 12-22 2024年
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60(5) 1721-1727 2023年9月
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Journal of Computational Physics 468 111505-111505 2022年11月 査読有り
MISC
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宇宙航空研究開発機構特別資料: 第53回流体力学講演会/第39回航空宇宙数値シミュレーション技術シンポジウム論文集 = JAXA Special Publication: Proceedings of the 53rd Fluid Dynamics Conference / the 39th Aerospace Numerical Simulation Symposium JAXA-SP-21-008 149-155 2022年2月14日第53回流体力学講演会/第39回航空宇宙数値シミュレーション技術シンポジウム (2021年6月30日-7月2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) The 53rd Fluid Dynamics Conference / the 39th Aerospace Numerical Simulation Symposium (June 30 - July 2, 2021. The Japan Society for Aeronautical and Space Sciences : Japan Aerospace Exploration Agency (JAXA), Online meeting) In this paper, aerodynamic characteristics around the blade of the hexacopter ''HAMILTON (HexAcopter for Martian pIt crater exploraTiON)'' for Mars exploration are investigated to obtain design knowledge regarding multicopter drone flying in Martian atmosphere. Reynolds-averaged Navier-Stokes simulation with the moving overlapped grid was employed for aerodynamic evaluation of two cases; one is hexa-rotor case and the other is single rotor case in order to compare single rotor case and hexa-rotor case and reveal unique characteristics of multirotor case. According to computational results, in both cases, hexa-rotor and single rotor, the maximum figure of merit could be observed at higher hovering thrust conditions. It is suggested that the baseline blade geometry could generate thrust efficiently at higher thrust conditions. The flow structure around the hexa-rotor can be classified into three groups; turn-in side where the flow was drawn the inside by blades rotation, turn-out side where the flow was put out to the outside by blades rotation, and the center side which was located between the turn-in and turn-out sides. The rotors of the center side took the low figure of merit compared with the other rotors because of aerodynamic interference from the turn-in side and the turn-out side rotors. Therefore, the total figure of merit of all rotors increased when the distance among rotors is increased. 形態: カラー図版あり Physical characteristics: Original contains color illustrations 資料番号: AA2130027012 レポート番号: JAXA-SP-21-008
書籍等出版物
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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
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54th AIAA Aerospace Sciences Meeting 2016年© 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. In this study, the effects of the computational spanwise domain length on the flowfield with massive separation and on the flowfield with dynamic stall are investigated by large-eddy simulation. The objective airfoil is NACA0012 and the chord-based Reynolds number is of 2.56 × 105. The objective flowfields are that around a fixed angle of attack of 10 and 25 degrees, and that around a pitching airfoil between AoA of 5 degrees and 25 degrees. The spanwise length effect become significant after the stall, as observed as the attenuation of the large vortices. Observations of the flowfield clarified that the undulation of two large vortices from the leading edge and the trailing edge is one of the mechanisms for the spanwise length effects. The qualitative analysis for this mechanism is performed to address the sufficient spanwise length, and the spanwise length have to be at least 1.0c for the flowfield with large vortex structures so as to resolve its spanwise distribution.
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大気球シンポジウム: 平成27年度 = Balloon Symposium: 2015 2015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 平成27年度（2015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: 16名ほか資料番号: SA6000044002レポート番号: isas15-sbs-002
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2015 IEEE Congress on Evolutionary Computation, CEC 2015 - Proceedings 2015年9月10日 Institute of Electrical and Electronics Engineers Inc.Two preferred approaches to implement selection in many-objective optimization are based on scalarizing functions and ϵ-dominance. This work introduces a Chebyshev Achievement Function in the parent selection step of the Adaptive ϵ-Sampling ϵ-Hood many-objective optimizer and studies the combined effect of the exploitative power offered by the scalarizing function with the highly dynamic and explorative features of the many-objective optimizer. Two parent selection methods are investigated to exploit solutions closer to the ideal point of the dynamically changing neighborhoods created by the many-objective optimizer. These parent selection methods are compared with the random selection within the neighborhood method used by the original many-objective optimizer. The algorithms are tested using many-objective problems with unimodal and multimodal fitness functions, fixing the number of generations with various population sizes and fixing the number of evaluations using various combinations of number of generations and population size.
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Proceedings of Turbulence and Shear Flow Phenomena 2015年7月
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45th AIAA Fluid Dynamics Conference 2015年© 2015, American Institute of Aeronautics and Astronautics, Inc. Contribution of large-scale vortex and fine-scale turbulent structure in separated flow control by DBD plasma actuator are investigated using computational results of large-eddy simulation and two-dimensional simulation. The Reynolds number based on chord length is 63, 000 and 10, 000. The angle of attack is 14 deg. for Re=63, 000 and 10 deg. for Re=10, 000. The DBD plasma actuator is set at the 5% chord length from the leading edge of NACA0015 airfoil and operated in burst mode. At the Re=63, 000, the spanwise vortex breaks down into the turbulent small-scale vortices. However, the spanwise vortices in the two-dimensional simulation maintained their structure while they convect to the downstream. Comparing the lift-to-drag ratio, similar values are obtained in the F+ = 1 and F+ = 6 case, while the F+ = 6 case shows higher than the F+ = 1 case in the large-eddy simulation. These results indicate that the effect of the small-scale vortices are important to reduce the recirculation region of the separated flow and improve the aerodynamic performance in the F+ = 6 case. On the other hand, at the Re=10, 000, similar trend of the flow fields are obtained from the large-eddy simulation and the two-dimensional simulation. This implies that the effect of the small-scale vortices to the separation control is small at this Reynolds number.
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ASME/JSME/KSME 2015 Joint Fluids Engineering Conference, AJKFluids 2015 2015年© 2015 by JSME. In this study, two-dimensional laminar simulation (2-D Lam), two-dimensional Reynolds Averaged Navier-Stokes simulation with the Spalart-Allmaras turbulence model (2-D RANS(SA)), and implicit three-dimensional large-eddy simulation (3-D LES) are performed for NACA0012, NACA0006, and Ishii airfoils at Rec =3.0×104. The relation between a predictability of airfoil aerodynamic characteristics and a dependence of airfoil geometry shape of each numerical method is evaluated at the low Reynolds number. Although little discrepancy is observed for the lift coefficient predictability, significant differences are presented in terms of the separation and reattachment points predictability depending on the numerical methods. The 2-D Lam simulation can predict the lift coefficients as well as the separation and reattachment points qualitatively as similar to the 3-D LES results except for the high angle of attack which is accompanied by the massive separation. The 2-D RANS(SA), the weak nonlinearity and stall phenomena for the lift coefficients are observed. A good predictability of the separation point are shown, however, it cannot be estimated the reattachment points due to the trend to predict widely for the separation region. The predictabilities of each numerical method appear regardless of the airfoil shapes.
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2015 IEEE CONGRESS ON EVOLUTIONARY COMPUTATION (CEC) 2015年 IEEEPreviously a preference relation based on the Chebyshev achievement function to solve many-objective optimization problems was proposed. Although using this preference relation improved the performance of NSGA-II, in this paper we present a new ranking method based on the E-indicator and the Chebyshev achievement function. The goal of this new method is two fold: i) to improve the performance of the original algorithm, and ii) to design a parallel sorting method in order to use it with large populations (>> 10(4) individuals). To do so, unlike the original approach, we have completely replaced the nondominated sorting by a method that ranks the population based on these two preference criteria. As the experiments show, the resulting algorithm outperforms both the standard NSGA-II and our previous approach in selected DTLZ problems. We also present a parallel implementation of the new sorting method. The running time analysis shows that the communication overhead is low enough to allow the speedup reach its peak for a large number of processors.
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第25回アストロダイナミクスシンポジウム講演要旨集 2015年
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第25回アストロダイナミクスシンポジウム後刷集 2015年
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Proceedings of AIAA Infotech @ Aerospace 2015年
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Proceedings of the 46th Lunar and Planetary Science Conference 2015年
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Proceedings of 2015 IEEE Congress on Evolutionary Computation 2015年
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Proceedings of 2015 IEEE Congress on Evolutionary Computation 2015年
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Proceedings of 30th International Symposium on Space Technology and Science (ISTS) 2015年
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53rd AIAA Aerospace Sciences Meeting 2015年© 2015 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. The main aim of this paper is to elucidate the mechanism of massive separation control by using a dielectric barrier discharge plasma actuator (DBDPA). A technique of design exploration is applied to find good operating-parameter combinations for the DBDPA. We consider a NACA 0015 airfoil with 16° angle of attack and Reynolds number Re = 63000. The flow without the control is massively separated, however we can suppress the separation using the DBDPA with the relevant operating parameters. Using good parameter combinations obtained by design exploration technique, the nature of the flow around the airfoil with and without control is explored in detail.
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大気球シンポジウム: 平成26年度 = Balloon Symposium: 2014 2014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 平成26年度（2014年11月6-7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: SA6000021006レポート番号: isas14-sbs-006
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Proceedings of the 2014 IEEE Congress on Evolutionary Computation, CEC 2014 2014年9月16日 IEEE© 2014 IEEE. In this paper, an algorithm for many-objective evolutionary computation, which is based on the NSGA-II with the Chebyshev preference relation, is applied to multi-objective design optimization problem of dielectric barrier discharge plasma actuator (DBDPA). The present optimization problem has four design parameters and six objective functions. The main goal of the paper is to extract useful design guidelines to predict control flow behavior based on the DBDPA parameter values using the resulting approximation Pareto set obtained by the optimization.
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最適化シンポジウム：OPTIS 2014年 一般社団法人日本機械学会DESTINY is injected to long elliptical orbit by Epsilon rocket launcher. If the apogee altitude of the injected orbit is high enough, it is achieved to ease the requirements for design and operation of the spacecraft. This paper investigates the ability of trajectory injection by means of 4-stage Epsilon rocket using the method of multi objective optimization under several flight constraints.
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Evolution, Complexity and Artificial Life 2014年1月1日 Springer Berlin HeidelbergThis work studies distribution search in the context of evolutionary many-objective optimization where, in addition to good convergence towards the optimal Pareto front, it is required to find a set of trade-off solutions spread according to a given distribution. We particularly focus on the effectiveness of Adaptive ε-Ranking, which reclassifies sets of non-dominated solutions using iteratively a randomized sampling procedure that applies ε-dominance with a mapping function f(x)↦ϵf′(x) to bias selection towards the distribution of solutions implicit in the mapping. We analyze the effectiveness of Adaptive ε-Ranking with three linear mapping functions for ε-dominance and study the importance of recombination to properly guide the algorithm towards the distribution we aim to find. As test problems, we use functions of the DTLZ family with M = 6 objectives, varying the number of variables N from 10 to 50.
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PROCEEDINGS OF THE ASME FLUIDS ENGINEERING DIVISION SUMMER MEETING, 2013, VOL 1B: SYMPOSIA 2014年 AMER SOC MECHANICAL ENGINEERSThe working parameters of the dielectric barrier discharge (DBD) plasma actuator were optimized to gain an understanding of the flow control mechanism. Experiments were conducted at a Reynolds number of 63,000 using a NAGA 0015 airfoil which was fixed to the stall angle of 12 degrees. The two objective functions are : I) power consumption (P) and 2) lift coefficient (C-l). The goal of the optimization is to decrease P while maximizing C-l. The design variables consist of input power parameters. The algorithm was run for 10 generations with a total population of 260 solutions. Although the number of generations and population size was limited due to experimental constraints, the algorithm was able to converge and the approximate Pareto-front was obtained. From the objective function space, we observe a relatively linear trend where C-l increases with P and after a certain threshold, the value of C-l seems to saturate. We discuss the results obtained in the objective space in addition to scatter plot matrix and color maps. This article, with its experiment-based approach, demonstrates the robustness of a Multi-Objective Design Optimization method and its feasibility for wind tunnel experiments.
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Proceedings of AIAA Science and Technology Forum and Exposition 2014 2014年1月
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日本機械学会第11回最適化シンポジウム2014講演論文集 2014年 一般社団法人日本機械学会Large-scale multiobjective design exploration using K computer is presented. This presentation includes aeroacoustic design optimization problem of a rocket launch site and aerodynamic design optimization problem of a plasma actuator applied to a wing model. Non-dominated solutions visualization tool named iSPM is also introduced.
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日本機械学会第11回最適化シンポジウム2014講演論文集 2014年 一般社団法人日本機械学会A novel algorithm for many-objective optimization based on continuous Ant Colony Optimization (AGO) is proposed.
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流体工学部門講演会講演論文集 2013年11月9日 一般社団法人日本機械学会In this study, multiobjective design exploration for a rocket launch site is conducted using evolutionary computation with large eddy simulation to understand the acoustic characteristics associated with various launch sites. The launch site is described by curved surface. The flat plate inclined with 45 degree is considered as the reference configuration. The objective functions of multiobjective aero-acoustic design optimization are, 1) minimization of averaged sound pressure level near the payload fairing, 2) minimization of maximum pressure on the curved surface of the rocket launch site, and 3) minimization of the change of the curved surface from the reference configuration. Three-dimensional compressible Navier-Stokes equations are solved with the modified weighted compact nonlinear scheme. The total number of evaluation is 2500, and the evaluation of one generation necessitates the use of 6500 nodes using "K" supercomputer. As the results of the flow field analysis of some characteristic non-dominated solutions show the characteristics of acoustic wave and the location of the maximum gradient of the curved surface.
共同研究・競争的資金等の研究課題
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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
