Effect of dynamic prehistory on aerodynamics of a laminar separated flow in a channel behind a rectangular backward-facing step

The effect of dynamic prehistory of the flow and the channel-expansion ratio on aerodynamics of a steady separated laminar flow behind a rectangular backward-facing step located in a plane-parallel channel is numerically studied. It is shown that the boundary layer upstream of the flow separation exerts a strong effect on flow characteristics behind the step. A decrease in the boundary-layer thickness in the cross section of the step leads to a decrease in the separation-region length, and an increase in the channel-expansion ratio with a fixed initial boundary-layer thickness and Reynolds number leads to an increase in the separation-region length.