Entropy-layer instabilities in plane supersonic flow

Entropy-layer instabilities in the supersonic flow over a blunt flat plate are investigated. Two types of entropy-layer instabilities are identified with the linear, local, parallel stability theory. The most amplified mode is a two-dimensional one. In order to validate the numerical findings experiments were carried out: The computed steady, laminar me-an-flow data agree with experimentally obtained mass-flow and Pitot-pressure distributions. The wall-normal distribution of the mass-flow eigenfunction of the most amplified entropy-layer instability is found in hot-wire data. The streamwise wave number and the wall-normal phase distribution of the numerically obtained density eigenfunctions agree with a Schlieren picture.