벽면의 형상 변화에 의한 난류 드래그 관련 Pocket Length Scale 저감연구

Abstract

The flow-surface interaction and resulting pockets is the case of a turbulence boundary layer. Conditionally sampled hot-wire measurements within the wall region show that a strong vortex forms within the pocket, bordering the upstream portion, which stay in the wall region. This vortex is the result of the rearrangement of existing sublayer vorticity and its amplification. The work in this area has been applied to the prediction and reduction of drag. The study is focused on determining change in the length scale of the pockets. An important relationship between pocket and modified wall has been found. By changing the upstream boundary condition at the wall, the length scale of pockets were decreased.