A comparison of three error estimation techniques for finite-volume solutions of compressible flows

Three techniques to obtain error estimates for finite-volume solutions on unstructured grids are compared in this study. The first estimation technique uses Richardson extrapolation involving three flow solutions on different grids. Error estimates on these grids are computed simultaneously with the order of convergence. The second technique is based on the difference between the computed solution and a higher-order reconstruction obtained using the least-squares method. Finally, a third technique solves an error equation driven by source terms computed from the flux jump at cell interfaces. The flows solved as test cases are governed by the two-dimensional Euler equations, and the discretization employs Roe's flux difference splitting scheme. Comparisons with exact errors allow the efficiency of each error estimation technique to be assessed for various types of flows.