Improvements in speed for explicit, transient compressible flow solvers

Abstract

Several explicit high‐resolution schemes for transient compressible flows with moving shocks are combined in such a way so as to achieve the highest possible speed without compromising accuracy. The main algorithmic changes considered comprise the following:

• replacing limiting and approximate Riemann solvers by simpler schemes during the initial stages of Runge–Kutta solvers, and only using limiting and approximate Riemann solvers for the last stage;
• automatically switching to simpler schemes for smooth flow regions;
• automatic deactivation of quiescent regions; and
• unstructured grids with cartesian cores or embedded cartesian grids.

The results from several examples demonstrate that speedup factors of 1:4 are attainable without compromising the accuracy of the traditional FCT schemes.

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