0320 Effect of Strong Spanwise Vortexes on the Frictional Drag in a Plane boundary layer downstream of a Backward-Facing Step

Abstract

Direct numerical simulations are performed in order to investigate the development of flow field and the friction drag in a subsonic plane boundary layer with a backward-facing step. The boundary layer is forced by normal velocity disturbance of various frequencies at the end of the back-step. The numerical results show that the large spanwise vortexes formed behind the backward-facing step and the observed growth rate of momentum thickness are smaller than flat plate turbulent boundary layer in this region.