Influence of viscous stresses on shock wave stability in gases

New shock jump conditions and the effect of curvature are derived, including viscous stresses within the shock layer and in the downstream gas flow. The main difference from the well-known Rankine–Hugoniot conditions is the existence of surface tension due to an anisotropy of viscous stresses in the layer. The classical problem of shock wave instability in gases has been solved with the new jump conditions. The surface tension is found to stabilize the shock wave generally whereas the viscous stresses in downstream flow destabilize it. The destabilizing effect dominates in the mode of spontaneous sound emission resulting in an absolute instability of the shock wave. This mode was previously considered to be neutrally stable.