2D Numerical Modeling of Dam Break flow in the Presence of Obstacles

Abstract

In this research, a numerical model was developed to simulate dam break flow in the presence of obstacles. The proposed model approximated the equations of moderately shallow water averaged at the finite volume method by implicit semi-Lagrangian method and the explicit and four-steps Runge-Kutta method with the fourth order accuracy was used to departure point determination. Radiation boundary conditions was applied to open boundaries and the model calculated the wet/dry boundary automatically. To demonstrate the accuracy of the proposed model, first, the solution obtained by this model was compared with analytical solution of dam break problem. Results were in good agreement with analytical solution. Then, the modeling results of dam break flow, in the presence of a square obstacle and four square obstacles, was compared with other researcher numerical model results. Finally, modelling results of dam break flow through an idealized city (a square city layout of 5×5 buildings) were investigated. In each experiment, the obstacles were non submerged and aligned with the approach flow direction. The results showed that the developed model had an acceptable accuracy at transient flow simulation in complex geometries and could appropriately predict the waves height and waves celerity caused by a dam break event in the presence of obstacles.

Keywords

• dam break
• obstacle
• runge-k
• semi-lagrangian
• shallow water equation