Numerical Study of the Effects of Side Weir Inlet Length on Characteristics of Main Channel Flow

In this study, the turbulent flow field in rectangular channels with side weir is simulated using the FLOW-3D software. To verify the modeling results, the experimental measurements obtained by Hager (1982) are used. Also, for simulating the flow turbulence the standard k-ε and RNG k-ε turbulence models are used. The numerical modeling results show that the RNG k-ε turbulence model has more accuracy. According to the modeling results, the RMSE and R2 values for the standard k-ε turbulence model are calculated 0.005 and 0.969, respectively. Meanwhile, these values for the RNG k-ε turbulence model are estimated 0.004 and 0.971, respectively. Also, analysis of the numerical results indicates the acceptable accuracy of the numerical model in predicting the experimental results. For example, the RMSE and correlation coefficient values for the mentioned model are calculated 0.004 and 0.971, respectively. Subsequently, the effects of the side weir inlet length on the flow pattern are investigated. For this purpose, three different numerical models with weirs with lengths of 1m, 0.7m and 0.5m are defined. According to the modeling results, by decreasing the inlet length the side Froude number value along the side weir decreases. In contrast, by decreasing the side weir inlet length the maximum value of the flow field pressure for the model with a inlet length of 0.5m is predicted. In other words, the maximum pressure values for the models with side weirs with lengths of 1m, 0.75m and 0.5m are calculated 271pa, 286pa and 317pa, respectively.