A dissipative finite element model for free surface flow

Abstract

A dissipative finite element model applicable to one-dimensional free surface flow is presented. The classical Galerkin formulation seems to be inappropriate to simulate open channel flow when discontinuities are introduced in the flow domain. A weighted residual formulation based on discontinuous weighting functions is presented, which provides better results than the standard Galerkin approximation. Thus the problem of the undesirable noise in the vicinity of the discontinuities is overcome and the finite element method becomes capable of simulating steep wave fronts. This dissipative model is applied to continuous flow in a section of the Axios river in Greece and it is also applied to discontinuous flow in a rough rectangular horizontal channel. The computational results are compared with those obtained by finite difference schemes and with experimental data.