Home – Home – Jornals – Journal of Applied Mechanics and Technical Physics 2016 number 5

The effect of the position of a passive porous coating on natural disturbances in a hypersonic boundary layer is studied experimentally. The experiments are performed in the flow around a sharp cone aligned at a zero angle of attack with the free-stream Mach number M_∞ = 5,8, stagnation temperature T₀ = 370±5 К, and unit Reynolds numbers Re_1∞ = 2,6 x 106, 4,6 x 106, 6,6 x 106, and 10⁷ m^-1. The wave characteristics of the boundary layer are calculated with the use of the linear stability theory for flow parameters corresponding to experimental values. A comparison of experimental and predicted results shows that the presence of a porous coating in the region where the second mode is unstable leads to reduction of its amplitude at the measurement point, whereas the presence of a porous coating in the region of second mode stability leads to enhancement of the amplitude.