후방 박리기포 감소를 위한 맥동제트의 최적화 연구

Abstract

The optimization study of pulsating jet was performed to reduce the separation bubble behind the fence. The experiments were carried out in circulating water channel and the vertical fence was submerged in the turbulent boundary layer. The frequency, jet speed and the location of jet nozzle from the fence were optimized. Each case was divided into 20 phases and phase-averaged DPIV method were applied to measure the velocity field. The results were compared with uncontrolled fence flow. From the experiments we found that the existence of specific frequency and location which are very effective to reduce the separation bubble behind the fence. In case of jet speed, higher velocity is good for reducing the reattachment length. The maximum 35% reduction of reattachment length appeared at StrH=0.05, Xv=1.75 and Vjet=2.0U0 condition.