Stability of non-adiabatic shock waves

The stability of two-dimensional shocks has been continuously investigated since the pioneering works of D’Yakov [1] and Kontorovich [2]. It was found that, in certain conditions related to the Rankine-Hugoniot slope, the shock oscillates permanently with the corresponding generation of entropic and rotational perturbations downstream, as well as the emission of constant-amplitude sonic waves, the latter being commonly referred as spontaneous acoustic emission (SAE).