Two-dimensional modelling of dam-break floods over actual terrain with complex geometries using a finite volume method

Based the total variation diminishing(TVD) finite volume method,a two-dimensional hydrodynamic model using unstructured triangular meshes is developed for modelling dam-break flooding under actual terrain with complex geometries.Details include uses of the Roe's approximate Riemann solver with the TVD-MUSCL(Monotone Upstream-centered Schemes for Conservation Laws) scheme as well as the procedure of predictor-corrector in time stepping,which can result in a second-order accurate solution for dam-break flows in both time and space.The moving boundary problem is resolved through the introduction of a minimum water depth concept that can efficiently treat the wetting and drying fronts during the model integration.The effect of using different values of the minimum water depth on the simulation of dam-break flows in the dry river bed is examined.We find that the minimum water depth can significantly alter the propagation of flood waves.Model results are also compared to the analytical solution under the idealized conditions,as well as two sets of dam-break data collected from flume experiments.Lastly,the model is validated using a real dam-break case with complex geometric conditions.The model simulation compares well with the observations and the other studies.