Galerkin finite element methods for the Shallow Water equations over variable bottom

TL;DR

This paper develops and analyzes Galerkin finite element methods for simulating the one-dimensional shallow water equations over variable bottom topographies, including error estimates and numerical experiments with various boundary conditions.

Contribution

It introduces finite element discretizations for the shallow water equations with variable bottom, providing error analysis and coupling with Runge-Kutta time stepping.

Findings

Error estimates for semidiscrete schemes

Successful numerical simulations of wave propagation

Effective handling of boundary conditions

Abstract

We consider the one-dimensional shallow water equations (SW) in a finite channel with variable bottom topography. We pose several initial-boundary-value problems for the SW system, including problems with transparent (characteristic) boundary conditions in the supercritical and the subcritical case. We discretize these problems in the spatial variable by standard Galerkin-finite element methods and prove L^2-error estimates for the resulting semidiscrete approximations. We couple the schemes with the 4th order-accurate, explicit, classical Runge-Kutta time stepping procedure and use the resulting fully discrete methods in numerical experiments of shallow water wave propagation over variable bottom topographies with several kinds of boundary conditions. We discuss issues related to the attainment of a steady state of the simulated flows, including the good balance of the schemes.