A real ghost fluid method for the simulation of multimedium compressible flow

In the previous ghost fluid methods (GFMs) developed, the focus is on the definition of ghost fluid states while the pressure and velocity in the real fluid sides are taken for granted, except for the correction made to the density at the real fluid nodes next to the interface to overcome the possible problems related to overheating. It has been found that such GFMs encounter many difficulties when applied to shock impedance matching (-like) problems due to the inability of accurately imposing interfacial conditions. By predicting the flow states for the real fluid nodes just next to the interface and the ghost fluid nodes using the Riemann problem solver, a more accurate interface boundary condition can be imposed and the said difficulties are mitigated to a large extent. This leads to the development of a proposed real-GFM in this work. A simple yet efficient extension of the present method to multidimensions is also introduced. In order to overcome issues associated with the severe bunching of level set contours due to the large flow velocity gradient, an extension (artificial) velocity field is constructed in the computation of the level set function. The present method is applied to various one- and two-dimensional problems involving strong shock-interface interaction and complex flow physics.