Optimizing the experimental study of the hydraulic of the internal flow the rock-fill dams and its methodology using the harmony search algorithm

One of the ways to control floods in the rivers is to build rock-fill dams without clay core in the flow path. These dams reduce the peak flow of the passing flood and increase the flood evacuation time. In the current research in the laboratory flume, models of rock-fill dam with aggregates with an average diameter of 2 cm with lengths of 155, 165 and 175 cm in the flow direction were built with different slopes and 3 different flow rates were considered for each model. In each discharge, the depth of the footing of wall was changed using the control valve, for 5 different modes, and a total of 405 tests were performed. After performing the dimensional analysis, dimensionless quantities were extracted and then by applying multivariable nonlinear regression, which shows the objective function related to the discharge coefficient and dimensionless quantities. By performing a sensitivity analysis on the removal of dimensionless quantities, it was found that by removing the quantity the height of the dam to the depth of the water upstream, the absolute average of the relative error increased by 2.5%. While by removing the quantity (slope of the abutment of the dam), the absolute average of the relative error increased by 8.6%.the quantity the height of the dam to the depth of the water upstream, the absolute average of the relative error increased by 2.5%. While by removing the quantity (slope of the abutment of the dam), the absolute average of the relative error increased by 8.6%