Receptivity of a high-speed boundary layer to temperature spottiness

• DOI: 10.1017/jfm.2013.111
• Publication Date: 2013-04-02T16:12:26Z
• Authors: A. V. Fedorov; A. A. Ryzhov; V. G. Soudakov; S. V. Utyuzhnikov
• Keywords: Receptivity; Leading edge; Eigenfunction

Abstract Two-dimensional direct numerical simulation (DNS) of the receptivity a flat-plate boundary layer to temperature spottiness in Mach 6 free stream is carried out. The influence parameters on process studied. It shown that spots propagating near upper boundary-layer edge generate mode F inside layer. Further downstream synchronized with unstable S (Mack second mode) and excites latter via inter-modal exchange mechanism. Theoretical assessments amplitude are made using biorthogonal eigenfunction decomposition method. DNS results agree theoretical predictions. If initiated pass through bow shock, dominant mechanism different. spot–shock interaction leads excitation acoustic waves, which penetrate into excite S. Numerical simulations show this provides instability amplitudes an order magnitude higher than case themselves.