An iterative method for unstructured dynamic-grid using springs based on LU-SGS (lower-upper symmetric Gauss-Seidel) is presented to reduce time of iterative in dynamic discontinuities simulation. Dynamic grid iterative time is as much as time of field itemtive as shock and flex-wall are numerical fitting by time-dependent Euler equations, because dynamic boundary is moving and whole unstructured grids are updated in every step of field iterative. A sparse matrix mapping grid topology based on spring strategy is presented. LU-SGS strategy is used in numerical simulation and dynamic grid is managed in order to solve the time choke point. Numerical results show that LU-SGS iterative method can be used to dynamic discontinuities fitting by implicit scheme. The presented method decreases more than 20% iterative time than classical SOR method.

In this paper, a modified scheme is developed, which can be used for calculation of axisymmetric fluid flow. A set of Euler equations of generalized Rieman variable is derived and solved by two step upwind scheme. The convergence is good because of the consideration of dependent domain of information. Because of using only one point except the unknown one, this scheme is simple and coding is easy. As a example, this scheme has been used for the inviscid subsonic-supersonic flow around blunt bodies at supersonic speeds, the merits of this scheme is demonstrated by these numerical experiments.