Comparison of 3D flow fields arising in mixed and standard unstructured finite elements

Computing 3D velocity fields is an important task in subsurface water flow analysis. While Finite Element (FE) simulations generally yields accurate estimates of the head, the numerical velocity may display errors and even unphysical behavior in some parts of the domain. Theoretically, the Mixed Hybrid FE (MHFE) approach provide a more accurate approximation to the velocities. In this communication we analyze a number of 3D–flow test cases, and compare the results obtained using FE and MHFE on tetrahedral meshes. Theoretical convergence estimates are numerically verified for a few simple problems. A more complex heterogeneous test case is used to show that, even for very fine meshes, the results obtained using the two discretization approaches may differ. Fulltext Preview Image of the first page of the fulltext document