| A new model for the dynamics of liquid/vapor phase transitions is presented. It is a combination of (viscous) strictly hyperbolic systems of conservation laws and reaction diffusion equations. The isothermal case corresponding to retrograde fluids. Sufficient condition for the existence and nonexistence of some types of traveling waves is given. Issues such as admissibility and stability of these traveling waves are considered. Major one-dimensional wave patterns observed in actual experiments with retrograde fluids are also observed in solutions of Riemann problems. A peculiar multi-dimensional wave pattern, symmetry breaking and ring formation, is also explained by this model. |