Numerical investigation of labyrinth stepped spillways’ performance on energy dissipation of skimming flow

Document Type : Research Article


1 University of Zanjan, Zanjan, 45371 - 38791, Iran

2 Department of Civil Engg., University of Zanjan


One of the main characteristics of stepped spillways is energy dissipation along the spillway during the flow transmission. This research is to propose a new form of spillways’ steps in order to achieve the maximum level of energy dissipation. In this paper flow hydraulics affected by geometric reform of steps to labyrinths with trapezoidal, triangular and rectangular shapes is investigated numerically using FLOW-3D model. The results show that production of flow interferences during flow passing over the labyrinth shapes is the main achievement of labyrinth stepped spillway. Also, trapezoidal labyrinth shape shows a better performance in accessing the maximum energy dissipation. In the same flow condition the rectangular, triangular and trapezoidal labyrinth shaped stepped spillways are effective in flow velocity reduction by 4.62%, 12.21% and 23.76% and also in more energy dissipation by 5.6%, 13.1% and 17% respectively compared to the usual flat stepped spillway. This is because of streamline interference and increasing the resistance against the flow and also the extension of recirculating region and production of more rotational flow. These types of spillways have fewer amounts of the residual head than that for flat stepped spillways. The residual head ratio (Hres/yc) in this type of spillway is ~2.57 while it is ~4.32 in the flat stepped spillway. Finally one can find these types of spillways as next generation of stepped spillways which increases the efficiency and hydraulic performance.


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