The effect of weak shock waves on the flow in the boundary layer of a plate when the - sweep angle changes

The experimental data on the effect of a pair of weak shock waves on the flow in the boundary layer of swept plates with initial angles χ = 35° and 40° at Mach number M = 2 are presented. The incident flow was disturbed using a weak shock wave (SW) generator made in the form of a two-dimensional sticker on the side wall or on the nozzle surface in the test section of the wind tunnel. For the latter case, shadow visualization of the flow past the models was carried out and the inclination angles of the weak SWs were determined. Measurements with a constant temperature hot-wire anemometer allowed us to record for the first time the effect of a weak SW from the leading edge of the sticker on the flow in the boundary layer of a flat plate with large sweep angles of the leading edge. On the model with χ = 35°, in the vicinity of the maximum effect of a pair of weak SWs, the flow characteristics were measured with a continuous change in the rotation angle of the model. The measurement results suggest that the sweep angle χ ≈ 48° is the critical sweep angle of the blunt leading edge, at which longitudinal vortices are not generated in the boundary layer by a “co-directional or overtaking” weak shock wave. The conclusions of previous studies that with an increase in the sweep angle along the leading edge, there is a decrease in the intensity of the effect of weak shock waves on the flow in the boundary layer, and that flow turbulization occurs for a model sweep angle of 50°, have been confirmed.