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چکیده
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The use of stepped spillways has become increasingly widespread due to low manufacturing costs and high efficiency. Hence, relevant research has significantly developed. So far, most of these studies are carried out on stepped spillways with an even steps arrangement. Yet, any change in step arrangement can be considered as an alternative in some cases. In this study, flow was simulated for four types of stepped spillways with different step arrangements using Fluent. Numerical analysis was done using three types of turbulence models including k-e (standard), k-e (RNG) and k-w (standard). These models are validated by comparing the results of the water level profile against laboratory data. Error values are computed. Based on root mean square error, the turbulence model k-e (RNG) presented more approximate results as compared to the laboratory results, regardless of the arrangement of the steps. After selecting the optimal turbulence model, pressure distribution on the spillway was computed by means of various steps arrangements. Based on the results, it was observed that the trend of pressure distribution was the same for all of the spillways; that is, it is reduced until reaching the edge of the steps, then increased as a result of water falling and hitting against the step floor, and reduced again along the step. Pressure values are larger for spillways with a smaller number of larger steps.
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