The two-dimensional Riemann problem for Chaplygin gas dynamics with three constant states

The Riemann problem for two-dimensional Chaplygin gas is considered for the case with three constant states. With the help of the generalized characteristic analysis method, the Riemann problem is classified into eight genuinely different cases; the structures of the Riemann problem solutions are analyzed and corresponding numerical solutions are illustrated using the numerical generalized characteristic analysis method. We find that a delta-shock wave appears and interacts with the simple waves in some cases.