Mathematical Simulation of Dam-Break Flow

Abstract

A one-dimensional mathematical model for the simulation of this flow is described, especially the boundary conditions and the application of numerical schemes to highly nonprismatic channels. To analyze the applicability and the accuracy of the mathematical model, four physical models were used. The conclusions are: (1)In relatively nonprismatic rivers the order of accuracy of the mathematical model described is 15% to 20%, and the model becomes unreliable in some extreme cases; (2)the main part of the error is due to the imperfection of the St. Venant equations used and only a smaller part to the inaccuracy of numerical methods; and (3)two explicit numerical schemes are investigated, the diffusive and the Lax-Wendroff scheme, the latter being more accurate. For the calculation of flow in highly nonprismatic channels, both schemes require completion of the St. Venant equations by a dissipative term in order to prevent instability and to achieve better simulation of the flow.