FLOW AND ENERGY DISSIPATION OVER A CYLINDRICAL STEPPED WEIR

Abstract

The great economic importance of increasing the energy dissipation flow rate in stepped weirs prompted researchers to make several changes to the geometrical shape. In this study, (36) physical models were constructed to compare cylindrical stepped weirs with traditional weirs. (27) Models of cylindrical stepped weirs and (9) traditional stepped weirs were based on three heights and three diameters of steps. There are three shapes of the weir steps (Fc = all the steps in a circular shape, i.e., without cutting), (Fc & Hc = one round and the other half cut, respectively) and (Hc = all the steps are cut in half). The study showed that the percentage of energy dissipation in weirs increases with the height of the weir (P). Increasing the diameter of the degree (D) and increasing the number of steps (n), and changing the shape of the degrees, as the case (Fc & Hc) was better than the case (Fc). In contrast, the state (Hc) was the best among the other instances in the percentage of flow energy dissipation. The cylindrical gradient weirs are more efficient than traditional stepped weirs by approximately (%10), and the highest value for the energy dissipation of the flow was obtained for stepped cylindrical weirs (%67.27).