Numerical 2D Vertical Simulation of Wave Propagation Due to Dam Break

Preparing for the consequences of dam failure is very important and should be considered. The failure of a dam can have major effects, such as injury and loss of life, economic, property and environmental damage. More than a century, scientists have seriously studied the dam failure. Flooding caused by a dam failure can occur in a relatively short period. Downstream communities located close to the dam typically have short warning times. Numerical modeling of dam-break flood analysis due to the shallow water equations are often developed as the next one. Initial studies in this area were done by Ritter [1] Dressler [2] and Stoker [3]. In the last decade, remarkable progress has been made in the field of numerical modeling of dam failure. Bellos et al. [4] applied a two-dimensional numerical model to simulate flood waves resulting from the instantaneous break of dams. The McCormack two step predictorcorrector scheme was used for the solution of the transformed system of equations. Comparisons between computed and experimental data showed a satisfactory agreement. The rapidly varied unsteady flow caused by the failure of a dam in a rectangular dry bed horizontal channel has been studied by Hassanzadeh [5]. In the literatures, many researchers have investigated various aspects of dam failure. In this paper, dam break and its flood wave propagation was simulated using finite volume method in twodimensional vertical condition. Numerical results are compared with experimental results for the evaluation ofnumerical model. In this paper, dam break wave propagation in two-dimensional vertical state is simulated by FLUENT model. FLUENT provides comprehensive modeling capabilities for a wide range of incompressible and compressible, laminar and turbulent fluid flow problems. To permit modeling of fluid flow and related transport phenomena inindustrial equipment and processes, various useful features are provided. A very useful group of models in FLUENT is the set of free surface and multiphase flow models. For these types of problems, FLUENT provides the volumeof- fluid (VOF) model. Robust and accurate turbulence models are a vital component of the FLUENT suite of models. The turbulence models provided have a broad range of applicability, and they include the effects of other physical phenomena, such as buoyancy and compressibility. Particular care has been devoted to addressing issues of near-wall accuracy via the use of extended wall functions and zonal model [6]. In this paper, numerical model was tested by three different turbulence models, k-ε, k-ω, and RSM. By use of statistical analysis method, NRMSE, the best turbulence model for 2D dam break, was obtained the k-ε standard(Table 1). Dam break have always been regarded as an extremely risky event and hence the research programs, government planning and investment in coastal dams are of the utmost importance. In this paper, dam break induced wave propagation was simulated using FLUENT model in two-dimensional vertical state, and numerical results were compared with experimental data for the evaluation and verification of numerical model. Dam break was simulated in both dry and wet bed performance for different sizes of the grid mesh, different discretization schemes (such as First Order Upwind, Second Order Upwind, Quick and Power Law) and different turbulence models (k-ε standard,k-ε RNG, k-ε Realizable, RSM and k-ω). Results show that the turbulence k-ε standard model and the First Order Upwind scheme are more accurate than others. After testing the sensitivity and accuracy of the model, simulation is done for basin slopes of 0, 1% and 2% and the roughness of the substrate with coefficients 0.009, 0.015, 0.0185, and0.0198 performance and results were analyzed. The results showed that the numerical model can be used to simulate a dam break in both dry and wet beds and provides acceptable results.