Study on Optimum Body Shape of Minimum Drag in 2-Dimensional Oseen Flow.

Research Project

Project/Area Number	61550320
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	船舶抵抗・運動性能・計画
Research Institution	University of Osaka Prefecture
Principal Investigator	HIMENO Yoji Univ. of Osaka Prefecture, Professor, 工学部, 教授 (50081394)
Co-Investigator(Kenkyū-buntansha)	BESSHO Masatoshi National Defense Academy, Professor, 機械工学科, 教授
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥1,800,000 (Direct Cost: ¥1,800,000) Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000) Fiscal Year 1986: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	Drag Minimization / Oseen / Viscous / Flow / 最適形状 / オセーン流れ / 粘性流 / 逆問題 / 最小化 / 最適化
Research Abstract	The present study deals with an inverse problem for obtaining body profiles with minimum viscous drag. In the preceeding first year, the authors applied an inverse procedure for drag minimization developed by the co-investigator, Prof. Bessho, to two-dimensional Oseen flow, and obtained symmetric optimum profiles about the origin. This second year, the method has veen extended to fore-aft asymmetric profiles with minimum drag under several restriction conditions. Numerical results and discussions on the optimum profiles are made. The procedure to find optimum profiles is an iterative method. The flow quantities for a given profile are firstly determined by integral equations using Oseen's kernel functions, and are numerically solved by a panel method. Then the optimum deformation is determined so that the drag is minimized, in which the governing equation is also expressed by a set of integral equations and the solution is obtained in the same way as the former step. Then the body profiles is deformed to obtain a new profile. This procedure is iterated until a convergence is reached. The optimum profiles thus obtaind are entirely coincide with those in the first year. For the case of center of profile and length prescribed, a new optimum profile of fore-aft asymmetric shape is obtained.