报告内容简介：

The pioneering work from Prof. Olivier Cadot (Grandemange et al, J. Fluid Mech, 2013)  firstly observed the bistable wake behind a flat-backed three-dimensional bluff body, manifest as stochastic switching between two asymmetry wake state. Our works investigated the effect of the body attitude (defined by the ground clearance, pith and yaw) and the Reynolds number on the wake transition for an Ahmed body. The study of the base pressure gradient reveals non-trivial and sharp transitions identified as significant changes of near wake orientation with the variation of the body attitude. The switching rate decreases with the increase of the Reynolds number, which is related to the viscous layer thickness of the boundary layer thickness at the trailing edge. In addition, the current work preliminarily investigated the application of the morphing technique on the drag reduction for the bluff body under a variable flow condition. All these works have been published in Journal of Fluid Mechanics, Physical Review E and Experiments in Fluids.