Babak Sanahmadi; Majeid Heydari; Saeed Gohari; Saeid Shabanlou
Abstract
In this paper, the flow in the vicinity of rectangular side orifices placed in main channels is estimated by means of the FLOW-3D model. To reconstruct the flow free surface, the volume of fluid (VOF) approach is utilized. In addition, the standard k-ε and RNG k-ε turbulence models are ...
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In this paper, the flow in the vicinity of rectangular side orifices placed in main channels is estimated by means of the FLOW-3D model. To reconstruct the flow free surface, the volume of fluid (VOF) approach is utilized. In addition, the standard k-ε and RNG k-ε turbulence models are employed to predict turbulence flow. According to the results obtained from the numerical modeling, the RNG k-ε turbulence model has higher accuracy than the standard k-ε. The analysis of the numerical modeling results proved that this model forecasts the discharge coefficient of side weirs with suitable accuracy. On the other hand, the mean absolute percent error (MAPE) is calculated equal to 12.204%. Also, the maximum pressure is simulated near the main channel bed. Moreover, the minimum pressure is estimated near the flow free surface. Regarding the numerical simulations, the maximum turbulence energy state occurs near the inlet of the side orifice and by increasing the side orifice dimensions the flow field turbulence energy value increases.
Hamed Azimi; Majeid Heydari; Saeid Shabanlou
Abstract
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 ...
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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.
