Numerical simulation of the effects of downstream obstacles on malpasset dam break pattern
نویسندگان
1 Department of Water Engineering, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran
2 Young Researchers Club, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran
3 Department of Science and Water Engineering, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran
doi
10.22126/arww.2018.1007چکیده
Dam break is an important phenomenon which significantly affects the environment as well as the inhabitants of the downstream areas of the dam. In the present study, the hydraulic break of Malpasset dam as a result of sudden flooding was simulated numerically using the FLOW-3D software. The two-equation k-ε turbulence models and RNG k-ε turbulence model were used to simulate the flow field turbulence. Also, the free-surface variations of the flow were simulated using the VOF (Volume of Fluid) scheme. The results obtained from the numerical model were in good agreement with those predicted by the EDF model. Based on the simulation results, the maximum pressure occurred at the lower layers of the flow and reduced as the free surface of the flow was approached. The maximum pressure increased at each point in time. The maximum longitudinal velocity occurred at the front of the advancing wave resulting from break of the dam, and subsequently decreased due to the increasing depth at the downstream of the dam. Additionally, the effects of obstacles with different shapes on the flow pattern arising from dam break (due to sudden flooding) were also investigated. Examination of these effects revealed that the cubic obstacle placed obliquely in the flow direction produced the maximum separation region at its downstream. Conversely, this separation region was eliminated completely when a cylindrical obstacle was used. The maximum and minimum Froude numbers were obtained for the flow encountering the perpendicular cubic obstacle and the flow impacting the cylindrical obstacle, respectively.
