A mass conservative well‐balanced reconstruction at wet/dry interfaces for the Godunov‐type shallow water model

Abstract

Summary This paper presents a novel mass conservative, positivity preserving wetting and drying treatment for Godunov‐type shallow water models with second‐order bed elevation discretization. The novel method allows to compute water depths equal to machine accuracy without any restrictions on the time step or any threshold that defines whether the finite volume cell is considered to be wet or dry. The resulting scheme is second‐order accurate in space and keeps the C‐property condition at fully flooded area and also at the wet/dry interface. For the time integration, a second‐order accurate Runge–Kutta method is used. The method is tested in two well‐known computational benchmarks for which an analytical solution can be derived, a C‐property benchmark and in an additional example where the experimental results are reproduced. Overall, the presented scheme shows very good agreement with the reference solutions. The method can also be used in the discontinuous Galerkin method. Copyright © 2016 John Wiley & Sons, Ltd.

Towards district scale flood simulations using conventional and anisotropic porosity shallow water models with high-resolution topographic information

“…no topography discontinuity at the edges is allowed. This type of topography discretization is advantageous for the solution of the Riemann problem across the edge but bears numerical challenges at wet-dry fronts [Fišer et al, 2016]. Özgen et al [2016] show that this closure is also valid for a conventional cell-centered Godunov-type finite-volume discretization that uses the hydrostatic reconstruction [Audusse et al, 2004].…”