Shock-Capturing Anomaly in the Interaction of Unsteady Disturbances with a Stationary Shock

Shock-capturing methods for numerical fluid dynamics are capable of correctly representing the flow conditions across shocks. However, there is no guarantee that the methods remain equally applicable for unsteady problems of shock–disturbance interaction. Based on the results of wide parametric computations, this paper demonstrates an inherent weakness of shock-capturing methods related to an ambiguous station of a stationary shock on a grid cell. To this end, the interaction of stationary shocks of different intensities with elementary waves of acoustic and nonacoustic nature is investigated in a simplified formulation. The computations reveal unpredictable postshock amplitudes of disturbances unless the viscous structure of the shock is sufficiently resolved. A shock resolution criterion and possible cures are suggested and discussed.