gray wolves algorithm

Considering the importance of redesign of dams spillways to provide optimum dimensions, the hybrid meta-heuristic based approach of Particle Swarm Optimization (PSO), Gray Wolves (GWO) and Direct Search Optimization (DSO) were proposed. In this approach, the spillway volume, which indicates the amount of concrete and cost, is considered as the objective function and spillway height, number of cycles, apex length and angle of wall are considered as decision variables. By implementing the proposed model, based on the Ute dam labyrinth spillway data, the spillway optimal dimensions were determined and compared with the other studies result. The results represent the very good performance of the proposed approach in generating global optimal solution, and non-hybrid use of DSO algorithm is not recommended due to network size constraint, increased computational cost and failure to achieve optimal solution. The optimal dimensions led to concrete saving and reduction of costs to 64% compared to the existing dam design. Investigating the optimal dimension of trapezoidal labyrinth spillway indicates that increase the flow capacity of the spillway to 15760 cubic meters per second. Finally, the comparison of the optimal dimensions obtained with two trapezoidal and triangular sections showed that the optimal form for labyrinth spillway is triangular.