이동 지면 근처의 정사각주 주위 공력 특성 연구

Incompressible RANS equations were adapted for investigating the effects of moving ground to the unsteady flow fields around a square cylinder as the gap height changes. The shear layer weakened near a moving ground can not prevent the interaction between the upper and lower separated shear layers of the cylinder. The critical gap height exits around G/D=0.3 is lower than G/D=0.55 in a stationary ground, and rapidly increases at G/D=0.3~0.45 thereafter almost uniform. The positive vortex induced by lower shear layer on the cylinder is detached from a moving ground and independently sheds downward. But in the case of stationary ground, the vortex connected to the separation bubble on the ground separates from the ground directly. The Drag of cylinder in a moving ground drastically increases due to the loss of pressure recovery induced by vortex shedding past a square cylinder in wake region at G/D=0.35~0.5.