Effect of the forebody curvature on the drag of an axi-symmetric body

Forebody;Curvature;Drag;Ellipsoid;621

공과대학 기계항공공학부(멀티스케일 기계설계전공) ;

University:서울대학교 대학원

关键词: Forebody;    Curvature;    Drag;    Ellipsoid;    621;   

Others  :  http://s-space.snu.ac.kr/bitstream/10371/123965/1/000000002641.pdf

美国|英语

来源: Seoul National University Open Repository

【 摘 要 】

In the present study, we investigate the eect of forebody curvature on adrag of an axi-symmetric body by numerical simulation. Curvature is applied onellipsoid with 4:1 aspect ratio and results are compared with 4:1 ellipsoid. TheReynolds number considered are 103 and 104 based on the free-stream velocity(u1) and minor axis of body (d).At Re = 104, 4:5% of drag reduction is achieved compared to that of 4:1ellipsoid. However, at Re = 103, variation of total drag is little. At bothReynolds number, as curvature increases, pressure drag increases because lowpressure occurs around forebody curvature. Contrary to pressure drag, frictiondrag decreases as curvature increases due to the formation of recirculation bub-ble on the concave region of curvature. Therefore, reduction of total drag isdetermined by amount of pressure drag increase and friction drag decrease.