We present numerical solutions of a two-dimensional Riemann problem for the unsteady transonic small disturbance equation that provides an asymptotic description of the Mach reflection of weak shock waves. We solve the equations in self-similar coordinates, and use local grid refinement near the triple point of the Mach reflection. The solutions contain a sequence of triple points and tiny supersonic patches immediately behind the leading triple point, formed by the reflection of weak shocks and expansion waves between the sonic line and the Mach shock. |