A novel multidimensional solution reconstruction and edge-based limiting procedure for unstructured cell-centered finite volumes with application to shallow water dynamics

On unstructured meshes, the cell-centered finite volume (CCFV) formulation, where the finite control volumes are the mesh elements themselves, is probably the most used formulation for numerically solving the two-dimensional nonlinear shallow water equations and hyperbolic conservation laws in general. Within this CCFV framework, second-order spatial accuracy is achieved with a Monotone Upstream-centered Schemes for Conservation Laws-type (MUSCL) linear reconstruction technique, where a novel edge-based multidimensional limiting procedure is derived for the control of the total variation of the reconstructed field. To this end, a relatively simple, but very effective modification to a reconstruction procedure for CCFV schemes, is introduced, which takes into account geometrical characteristics of computational triangular meshes. The proposed strategy is shown not to suffer from loss of accuracy on grids with poor connectivity. We apply this reconstruction in the development of a second-order well-balanced Godunov-type scheme for the simulation of unsteady two-dimensional flows over arbitrary topography with wetting and drying on triangular meshes. Although the proposed limited reconstruction is independent from the Riemann solver used, the well-known approximate Riemann solver of Roe is utilized to compute the numerical fluxes, whereas the GreenGauss divergence formulation for gradient computations is implemented. Two different stencils for the GreenGauss gradient computations are implemented and critically tested, in conjunction with the proposed limiting strategy, on various grid types, for smooth and nonsmooth flow conditions. Copyright (c) 2012 John Wiley & Sons, Ltd.