Linear development of controlled disturbances in the supersonic boundary layer on a swept wing at Mach 2

Abstract

Experimental results are presented on the linear development of a wave train in a three-dimensional supersonic boundary layer on a swept wing with 45°-sweep angle at Mach number M = 2.0. Artificial disturbances in the boundary layer were excited by periodical glow discharge mainly at frequencies 10 and 20 kHz. The maximum of the controlled pulsation amplitude was localized in the boundary layer in normal to the swept-wing surface direction for spatial amplitude distributions as well as for the amplitude wave spectra. The asymmetry of the wave characteristics of the unstable disturbances in the boundary layer of a swept wing caused by the presence of crossflow is confirmed. The stability characteristics, including dispersion relations and amplification rates over a wide range of wave inclination angles, are obtained for disturbances with prescribed frequencies 10 and 20 kHz.

On the development of controlled stationary and travelling disturbances in the supersonic boundary layer of a swept wing

“…Recall that the asymmetry of the amplitude distributions along the spanwise z′-coordinate, relative to the position of the discharge (z′ = 0 mm), are associated with the presence of crossflow on the swept wing. The wave train is spread along the leading edge of the model in the direction opposite to the crossflow, and this is consistent with previously obtained results for the same Mach number (2.0) [11,12]. Figure 3 shows the amplitude β′-spectra of the controlled disturbances at frequency 20 kHz.…”

“…Results concerning the development of natural disturbances are presented in detail in [11,12]. Note that the source of the controlled disturbances is located in the linear region of the natural fluctuation development and, moreover, the frequency of the artificial pulsations (f = 20 kHz) falls within the frequency range for most unstable natural disturbances.…”

“…Such a technique allows one to observe the linear development of a wave train with frequencies of 10 KHz and 20 kHz, on a swept wing at Mach number M = 2.0. [11,12]. Moreover, at ITAM SB RAS, the technique of pulsed excitation of a wave packet with a broad disturbance spectrum has been implemented to obtain wave characteristics for a wide range of frequencies [13].…”

On the oblique breakdown mechanism in a supersonic boundary layer on a swept wing at Mach 2

“…The method of controlled disturbances allowed to find out the wave characteristics of the boundary layer [19,20] and to determine the basic mechanisms of transition in supersonic boundary layer on a flat plate [21]. These results are concerned to the smooth surface of the flat plate.…”

The evolution of mass flow and total temperature pulsations in flat plate boundary layer at M=2.5

“…The disturbances with known initial characteristics are artificially introduced into the flow. The study of the evolution of artificial controlled perturbations allows one to find out the wave characteristics of the boundary layer [1][2][3][4][5][6]. Experiments with the controlled pulsations are very important and play a vital role in validating theoretical results.…”