Stability of Hypersonic Boundary Layer on Porous Wall with Regular Microstructure

Numerical modeling of the stabilization of a supersonic flat-plate boundary layer by a porous coating

“…The coating parameters were so chosen that in the streamwise direction about 20 pores for s = 3r 0 and 15 pores for s = 4r 0 fell in the second mode wavelength, which was equal to λ ≈ 0.02 for a disturbance frequency ω = 260. For such high pore concentrations and small radii, the coating roughness is apparently negligibly small; at the same time, the porous layer is capable of effectively absorbing disturbances penetrating into it [6,7,11]. The pressure disturbance distributions over the solid (Fig.…”

“…Then, it transforms gradually into the second mode and grows more intensely at x > 0.7. The linear stability theory and experiments [9][10][11] indicate that a porous layer has a stabilizing effect on the second mode and a slightly destabilizing effect on the first mode. Therefore, the S mode must become less stable Fig.…”

“…Thermoanemometric measurements and theoretical calculations performed on the basis of the linear stability theory showed that this coating has a strong stabilizing effect on the second mode and a slight destabilizing effect on the first mode. The second set of experiments [11] was performed in the same wind tunnel on a cone having a coating with a regular microstructure (thin perforated sheet similar to that used in experiments [8]). It was shown that this coating also stabilizes the second mode.…”

Experimental study of the effect of a passive porous coating on disturbances in a hypersonic boundary layer. 1. Effect of the porous coating length

“…Fedorov et al [1] proposed to use passive porous coatings for hypersonic boundary layer stabilization. Calculations on the basis of the linear stability theory [1][2][3][4] showed that the passive porous coating partly absorbs the energy of the second mode of disturbances, which may increase the length of the laminar segment. Results of experimental investigations of the effect of coatings with a regular [1] and random [5] microstructure on the laminar-turbulent transition confirmed the possibility of increasing the laminar segment length.…”

“…The evolution of disturbances on the surface of a sharp cone with a passive porous coating was experimentally studied in [2][3][4]6]. The development of natural disturbances and artificial wave packets was considered.…”