Experimental study of the influence of parameters of a passive porous coating on the development of disturbances in a hypersonic boundary layer

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

“…A further increase in the coating thickness did not lead to an increase in coating efficiency; the maximum degree of stabilization of the second mode for coatings with porosity values of 44 and 64% was almost identical. The results of calculations [11] performed for the test conditions of [10] agree well with the experimental data. Wartemann et al [12] reported the results of a numerical study of the effect of the pore shape and size on the character of flow disturbances, which also agree with our experimental data [10].…”

“…The effect of the thickness and degree of porosity of the passive porous coating on the second mode of disturbances was studied in [10]. The coating efficiency was demonstrated to increase as the porous coating thickness was increased up to a certain value.…”

Investigation of the influence of a slots depth on disturbances in a hypersonic boundary layer

“…Theoretical and experimental works show that using ultrasonic absorptive coating allows to reduce the intensity of most unstable ultrasonic disturbances (second mode disturbances) in hypersonic boundary layers [3][4][5][6][7][8][9]. Experimental investigations confirm that the ultrasonic absorptive coatings effectiveness depends on its depth [6,7].…”

Experimental investigation of the influence of the passive porous coating on laminar-turbulent transition of the hypersonic boundary layer of the sharp cone at angles of attack

“…The previous experimental studies are shown that it's possible either to reduce or magnify the energy of second mode disturbances using the porous coating with different length on the cone [11]. It indicates that the ability of the porous coating to delay transition is not predictable in case of small varying hypersonic boundary layer parameters.…”

“…The layers are turned with respect to each other by the angle of 45˚. The coating thickness are chosen as most effective according to the experimental work [11]. The thickness equals to 0.18 mm.…”