A comparison of refinement indicators for p-adaptive discontinuous Galerkin methods for the Euler and Navier-Stokes equations

Abstract

This paper presents an analysis of refinement indicators for the numerical solution of the Euler and the Navier-Stokes equations using a p-adaptive discontinuous Galerkin (DG) method. Residual error, discretiza-tion error and feature-based indicators are studied in the context of p-adaptive DG simulations of two inviscid flow configurations, namely, the flow over a Gaussian bump and the flow past a circular cylinder. As expected, the superiority of local p-refinement as compared to uniform p-refinement is clearly observed. The results obtained highlight the efficiency of the considered refinement indicators with respect to an indicator based on the local entropy error. In particular, they identify regions where numerical errors are being produced and not those where errors are being convected. Finally the p-adaptive algorithm is applied to the simulation of the laminar flow past a circular cylinder at Re = 40. The great potential of the spectral decay 1 and VMS 2 indicators, which combine accuracy and computational efficiency, is also demonstrated.