A Study on the Behavior of Spheroid Configuration Bobbin

Kang, Seung-Hee; Ahn, Sung-Ho; Rim, One-Kwon; Kim, Hye-Ung

Journal of the Korea Institute of Military Science and Technology 2010;13(5):717-724.

Seung-Hee Kang, Sung-Ho Ahn, One-Kwon Rim, Hye-Ung Kim

¹Chonbuk National University
²
³

회전타원체 보빈 형상의 거동에 관한 연구

강승희, 안성호, 임완권, 김혜웅

¹전북대학교
²국방과학연구소
³전북대학교 대학원

Abstract

The initial trajectory of a spheroid configuration bobbin for precision guidance has been investigated by analyzing its aerodynamic load and six-degree-of-freedom motion. The effects of changes in the spheroidal head configuration, flow angle and lateral center-of-gravity offset are numerically studied using the commercial software "FLUENT". A wind tunnel test is also conducted to validate the numerical scheme and to examine effect of the Reynolds number on the flow around the bobbin. It is shown that the size of the separation bubble formed on the surface decreases significantly when the Reynolds number is varied between 110,000 and 140,000. At a zero flow angle, an oblate spheroidal head shows relatively moderate rotation while a prolate spheroidal head shows rapid rotation. The bobbin with a spherical head shape has little effect on the flow direction; however, the oblate bobbin is sensitive to the flow angle. The roll motion of the bobbin is greatly influenced by the lateral center-of-gravity offset and maximum dispersion is observed at half of the radius.

Key Words: Bobbin, Graphite Bomb, Trajectory, Wind Tunnel Test