Comparisons between the cell-centered and staggered mesh Lagrangian hydrodynamics

The object of this study is to investigate the accuracy and stability of the cell-centered and staggered mesh 2-D Lagrangian hydrodynamic methods. For the cell-centered scheme, we try to remove two of the well known difficulties associated with the staggered mesh hydro such as Gibbs phenomena and artificial viscosity. In the control volume cell-centered method, we use a generalized Total-Variation-Diminishing (TVD) scheme which has the nature of monotonicity But it requires a tactful treatment on defining the vertex velocity. In the staggered mesh method, a modification to the artificial viscosity is made so that the acceleration from the artificial viscosity will project onto the unit vector in the direction of local acceleration. This projection eliminates “false heating” and helps maintain a stable computation grid. Three sample problems are computed using both methods and the results are discussed.