High-frequency instabilities in supersonic compression-ramp flow

We consider high Reynolds number supersonic flow over a compression ramp in the triple-deck formulation. Previous studies of compression-ramp stability have shown rapid growth high-frequency disturbances initial-value computations; however, no physical or numerical origin has yet been identified robustly. By considering linear perturbations to steady solutions, we show that instabilities observed previous do not rate is described by integral eigenrelation Tutty & Cowley ( J. Fluid Mech. , vol. 168, 1986, pp. 431–456) for (long-wave) Rayleigh instability. solve both temporal and spatial instability problems limit asymptotically large wavenumber $K$ (or equivalently frequency) remains $o(K)$ being dominated higher-order terms expansion at moderate angles.