The limit behavior of the Riemann solutions to the generalized Chaplygin gas equations with a source term

The paper is concerned with the limit behavior of the Riemann solutions to the inhomogeneous generalized Chaplygin gas equations. The formation of delta shock waves and the vacuum states are identified and analyzed as the pressure vanishes. Unlike the homogeneous case, the Riemann solutions are no longer self-similar. As the pressure vanishes, the Riemann solutions to the generalized Chaplygin gas equations with a friction term converge to the Riemann solutions to the pressureless gas dynamics model with a body force.