Evaluation of the hydraulic behavior of the composite hydraulic structure considering a bed flume with special obstacle

The experimental simulation between the composite hydraulic structure and the found obstacles in the downstream region is a challenging process due to the energy losses and kinematic dissipation. The current work focuses on a comparative analysis of free flow conditions that exist without obstacles and submerged flow conditions that occur due to obstacles. It indicates the evaluation of hydraulic variables and geometrical variables of composite hydraulic structure for both flow conditions. In addition, it includes an investigation of the interaction among these variables. The hydraulic variables include actual discharge, flow velocity, flow cross-sectional area that crosses the gate, downstream water depth, discharge coefficient, Reynolds number and, Froude number, while the vertical distance between the weir and gate represents the geometry variable. The interference between the weir discharge and gate discharge plays a significant role in the result fluctuation and variation for both flow conditions, while the form and size of the obstacles only have a major effect on the submerged flow. For both flow conditions, the water depth is investigated; there would be a drastic increase in water depth by using obstacles in the downstream area as compared with not using the obstacles. This study adopts different obstacles in shape and size, therefore, the variation of maximum and minimum water levels related to the location will occur.