Experimental Investigation of Laminar-Turbulent Transition Process in Supersonic Boundary Layer Using Controlled Disturbances

Due to significant efforts to prove of linear stability theory by experimentally [1–8] it became possible to make progress at studying of nonlinear stability of supersonic boundary layer. Experiments shown that subharmonic resonance takes place in supersonic boundary layer [9]. A transformation of wave spectra from three- to two-dimensional disturbances at increasing Reynolds number was found later [10]. Up to now experiments and nonlinear theory have developed independently. Recently theoretic model of subharmonic resonance relevant to experiments [9] was developed by Tumin [11]. However, streamwise vortex growth still was not tested in experiments as predicted by theory [12]. More detail review of nonlinear results obtained for boundary layer is presented in [11]. In the paper, we discuss an initial amplitude influence of artificial disturbances on nonlinear development of wave trains and origin of sound radiation by supersonic boundary layer.