Two-dimensional direct numerical simulation (DNS) of the porous coating stabilization effect is carried out for near-wall flows over a flat plate, sharp cone and compression corner at freestream Mach numbers 5-6. Numerical data obtained for disturbances propagating in the boundary layer on a flat plate agree satisfactory with the linear stability theory (LST). The coating end effects, which are associated with discontinuity of boundary conditions at the juncture between solid and porous walls, are considered. It is found that the end effects are localized over 2-3 disturbance wavelength and can be neglected in calculations of the integral performance of porous coatings. Receptivity of supersonic boundary layer to fast and slow acoustic waves is modeled. It is shown that the porous coating weakly affects acoustic disturbances and initial amplitudes of the boundary-layer modes, while it strongly suppresses the second-mode amplification. For the compression corner flow, DNS shows that the porous coating weakly affects high-frequency disturbances in the separation region and strongly stabilizes them in the reattached boundary layer downstream from the separation bubble. These numerical studies confirm robustness of the porous coating stabilization concept.
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