AN EXPERIMENTAL INVESTIGATION OF THE COHERENT STRUCTURES OF THE FLOW BEHIND A BACKWARD FACING STEP

The coherent structures of the flows in the recirculate region, reattaching region and tht boundary layer redeveloping region behind a backward facing step were investigated experimentally. The step height is 2cm, and the Reynolds number based on step height is 1900 to 3400. The flow structures were visualized by hydrogen bubble technique. The large vortical structures in the outer region and the streaky structures in the wall region were investigated.