進行波状壁面変形によって制御された乱流境界層流れにおける渦のステレオPIV計測

抄録

Streamwise vortices increase friction drag in a turbulent boundary layer by vigorous momentum transport near the wall. This study aims to clarify the change of vortical structure with decreasing turbulence in turbulent boundary layer flows where drag is reduced by traveling wavy control. A three-dimensional velocity field was constructed for a flow with a developed turbulent boundary layer using stereo PIV of the channel cross-section multiple times and the Taylor hypothesis. Although traveling wave control did not eliminate the streamwise vortices throughout the entire region, the vorticity in the streamwise direction tended to decrease. Furthermore, the instantaneous vorticity fields at each cross-section revealed that the streamwise vortices were restricted below y+ < 50 and that their shape and position in the wall-normal direction changed according to the wall deformation.