국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	NEW Aerodynamic Information Obtained from the Solution of the Inverse Problem for Aerofoils
저자	Masashi SHIGEMI
Keyword	aerofoil; direct problem; inverse problem; boundary layer; displacement thickness; Reynolds number
URL	http://send.nal.go.jp/send/jpn/dlpdf.php3/naltr01172.pdf?id=NALTR0001172
보고서번호	NAL TR-1172
발행년도	1992.7
출처	NAL (National Aerospace Laboratory of Japan)
ABSTRACT	of the inverse problem is applied differently because the flow input was measured in a wind tunnel experiment rather than being idealized.Investigation of the resultant aerofoil shape provided useful information on the real viscous flow characteristics around the aerofoil as well as on the feature of direct problem solution method to analyse it.The aerofoil shape from the inverse probrem solution was found to be thicker than that of the one installed in the wind tunnel,with its trailing edge open.This difference is due to the boundary layer around the wind tunnel aerofoil,since inviscid flow was assumed in the computation and the actual fluid in the wind tunnel was viscous.The additional thickness of the converged aerofoil is of the same order as the displacement thickness of the boundary layer;hence demonstrating the reliability of the popular approach to incorporate viscous effects into the inviscid analysis by solving the direct problem for an aerofoil with its shape modified by adding the displacement thickness of the boundary layer to the original shape.Inviscid flow analysis around the output shape showed that the applied inverse problem solution was quite accurate when the Reynolds number was 1.0×105.At a higher Reynolds number,the solution did not converge into an aerofoil.The origin of the locally irregular pressure distribution,which was generated on an apparently smooth aerofoil surface,was determined to be an irregularity in the second derivative of the surface coordinates.