A second-order Godunov scheme on a spatial adapted triangular grid

Abstract Spatial adaptation procedures for the accurate and efficient solution of unsteady inviscid flow simulation are described. The adaptation procedures were developed and implemented applying a second-order Godunov scheme. These procedures involve mesh enrichment/coarsening to either add/remove vertices in high/low gradient regions of the flow, respectively. The goal is to achieve solutions of high spatial accuracy at minimal computational cost. The paper describes a very effective error estimator to detect high/low activity regions of the flow to be enriched or coarsened, respectively. The error estimator is based on total energy and density fluxes into the cell combined with gradient of density. Included in the paper is a detailed description of the direct dynamic refinement method that is used for adaptation. A detailed simulation of a reflection and diffraction of multiple shock waves flowing over a diamond shape wedge is presented and compared with experimental results. The simulated results are shown to be in excellent agreement with the experiment primarily in that all the complicated features of the physics are accurately accounted for and the shock waves, slip lines, vortices are sharply captured.