Experimental investigation on laminar boundary layer separation over a backward-facing step

The differential LDA system has been used to measure the laminar boundary layer separation, reattachment, and redevelopment up to a turbulent boundary layer over a backward-facing step. The distributions of the mean velocity and turbulent intensity are obtained. It is found that, in the present experiment, the flow is a transitional boundary layer at the reattachment position, which further develops until a turbulent boundary layer was formed. In the turbulent boundary layer region, the distribution of the mean velocity obeys the 'log-law' except the greater value of the integral constant in comparison with that obtained in the obtained in the turbulent boundary layer over a flat plate.