Effect of the Riblet in the Transitional Flow Region

Kento Kaneko, Akira Oyama, Aiko Yakeno

JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 73(2) 33-41 2025年
Multiobjective Evolutionary Topology Optimization Algorithm Using Quadtree Encoding

Naruhiko Nimura, Akira Oyama

IEEE Access 12 73839-73848 2024年5月査読有り責任著者
Mach Number Effect on the Drag Reducing Performance of the Riblet in the Transition and Turbulent Flow

Kento Kaneko, Akira Oyama, Aiko Yakeno, Shingo Hamada

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.
Viscous Drag Reduction Effect of Riblet at Cruising Speed of Transonic Aircraft

Kento Kaneko, Akira Oyama, Aiko Yakeno

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 ! = . .
Development and Application of Three-Dimensional High-Degree-of-Freedom Multiobjective Design Optimization Method

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

もっとみる

MISC

詳細FMEAデータをもとにしたインターフェース情報の可視化

藤本圭一郎, 飯塚宣行, 大山聖, 角有司, 藤井孝藏, 南里秀明, 沖田耕一

第17回日本機械学会設計工学システム部門講演会論文集, 2007 205-208 2007年

In order to improve an efficiency of failure analysis process by using failure mode and effect analysis (FMEA) and failure tree analysis (FTA), detailed FMEA/FTA support tool is developed. By using this tool, failure mechanisms can be analyzed with FMEA approach as well as FTA approach. In order to improve coverage of the extracted failure modes, new failure analysis approach is proposed, which is based on the interface N2 chart. Interface N2 chart is N2 chart which is extended to express the interface of mechanical system. Interface N2 chart can also be used to visualize the failure analysis result to describe system structure based on the knowledge obtained in failure analysis such as causal relationship of fault propagation. New schematic visualization method is discussed to realize useful visualization tool which promotes comprehensive understanding of failure mechanism.
401 多目的シックスシグマ手法の開発と火星航空機翼型ロバスト空力設計への適用(進化的計算とその応用(1),OS16 進化的計算とその応用)

下山幸治, 大山聖, 藤井孝藏

計算力学講演会講演論文集 2006(19) 189-190 2006年11月2日
910 感圧・感温塗料を用いた斜め平板衝突噴流の解析(1)(OS9-2 高速流れと衝撃波現象の解明と制御,OS9高速流れと衝撃波現象の解明と制御)

伊藤匡人, マキロイ寛済, 大山聖, 藤井孝藏, 林光一

流体工学部門講演会講演論文集 2006 "910-a" 2006年10月28日
910 感圧・感温塗料を用いた斜め平板衝突噴流の解析(2)(OS9-2 高速流れと衝撃波現象の解明と制御,OS9高速流れと衝撃波現象の解明と制御)

伊藤匡人, マキロイ寛済, 大山聖, 藤井孝藏, 林光一

流体工学部門講演会講演論文集 2006 "910-1"-"910-4" 2006年10月28日

Flow fields of the supersonic jets impinging on an inclined flat plate at high plate-angles are experimentally investigated using surface pressure measurement with pressure sensitive paint and Schlieren flow visualization. While Type I flow type is dominant at high plate angles, the present research found a new flow type "TYPE I with bubble" at plate angle between 60 and 80 degrees. The flow classification according to L/L_s' and plate angle indicated that the constant x/L'_s curve doesn't represent the boundary of Type I and Type II anymore at high plate angles between 60 and 90 probably because Type II flows at low plate angles and high plate angles is different phenomena. This study also indicates that the curve dividing Type I and Type I with bubble regions is same as the curve dividing Type II and Type II with bubble regions.
1004 有機ELを用いた感圧塗料圧力計測系による平板衝突噴流の解析(OS10-1 流れの可視化・PIV,OS10 PIV・可視化画像計測,オーガナイズドセッション)

伊藤匡人, 大山聖, 藤井孝藏

流体工学部門講演会講演論文集 2005 144-144 2005年10月28日
1515 高効率かつ利便性に優れたロバスト最適化手法の開発 : 多目的シックスシグマ手法(OS17 変動-バラツキを考慮した設計手法および設計例II)

下山幸治, 大山聖, 藤井孝藏

設計工学・システム部門講演会講演論文集 2005(15) 237-240 2005年8月2日

An efficient and useful robust optimization approach, design for multi-objective six sigma (DFMOSS), has been developed. The DFMOSS couples the ideas of design for six sigma (DFSS) and multi-objective genetic algorithm (MOGA) to solve drawbacks of DFSS. DFMOSS obtains trade-off solutions between optimality and robustness in one optimization. In addition, it does not need careful parameter tuning. Robust optimizations of a test function and welded beam design problem demonstrated that DFMOSS is more effective and more useful than DFSS.
JAXA/ISASにおけるロケット・宇宙機研究開発へのCFDの活用(<特集>ロケット・宇宙機周りの流れ)

大山聖, 藤井孝藏

ながれ : 日本流体力学会誌 24(3) 289-296 2005年6月25日
感圧・感温塗料圧力計測系のための取得画像後処理ソフトウェアの開発

大山聖, 藤松信義, 伊藤匡人, 藤井孝藏

可視化情報学会誌. Suppl. 25(1) 313-316 2005年3月15日
感圧・感温塗料を用いた斜め平板衝突噴流の解析

伊藤匡人, 大山聖, 藤井孝藏, 林光一

可視化情報学会誌. Suppl. 25(1) 317-320 2005年3月15日
火星探査飛行機翼型の空力設計最適化

大山聖, 藤井孝藏

日本機械学会流体工学部門講演会講演論文集, 2005 301-301 2005年
C114 低レイノルズ数翼型の設計最適化(C-11 形状表現と最適化(1),一般講演)

大山聖, 藤井孝藏

日本流体力学会年会講演論文集 2004 84-85 2004年

Low Reynolds number airfoil design optimization is demonstrated. A two-dimensional Navier-Stokes solver is used for aerodynamic performance estimation of the airfoil design candidates because the viscosity effect is not negligible at low Reynolds number flight condition. An evolutionary computation is used for robust airfoil design optimization. The result demonstrated that the optimized airfoil is a very thin airfoil with significant camber. The result also showed that the low Reynolds number airfoil has time variation in its lift and drag.
進化的計算法によるトレードオフの発見について

大林茂, 佐々木大輔, 大山聖

計算数理工学レビュー 2003(1) 13-26 2003年10月
実数領域適合型進化アルゴリズムによる空力最適化

大林茂, 大山聖

年会一般講演 18 373-374 1999年7月29日
翼の空力設計への進化アルゴリズムの適用

大山聖, 大林茂, 中橋和博, 廣瀬直喜

計算工学講演会論文集 4(1) 475-478 1999年5月26日
三次元翼の空力最適化(第14回航空機計算空気力学シンポジウム論文集)

大山聖, 大林茂, 中橋和博, 中村孝

航空宇宙技術研究所特別資料 34 107-112 1997年

書籍等出版物

Constraint-handling in evolutionary aerodynamic design

Akira Oyama

Springer Verlag 2009年 Refereed

Constraint-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.