Joint Influence Of Surface Roughness And Permeability On Stability And Transition Of Mach = 2 Boundary Layer

Joint theoretical and experimental investigation of the influence of surface permeability and roughness on stability and laminar-turbulent transition of the supersonic flat-plate boundary layer at free-stream Mach number M = 2 have been performed. Good quantitative agreement of experimental data obtained with artificially generated disturbances performed on models with various porous inserts and calculations based on the linear stability theory has been achieved. At research of the joint effect of the model surface permeability and roughness on the boundary layer stability and transition, it is shown that, as a certain (critical) roughness value is reached, with the rough and porous coating thickness increase, the boundary layer stability diminishes and the laminar-turbulent transition is displaced toward the model leading edge.