Simulation of flow and Hydraulic of bottom in take structure using the flow3D software

Bottom intake is an intake structure which can be considered as an alternative for regular intakes in mountain streams Water in in taking from river are very vast and complicated issues, each project has special characteristics which should be considered. Water intake from riveris generally based on Pump and gravity method. The gravity method is more useful and common because of continuity and no need spare energy rather than pump method. The different methods are possible at gravity methods these methods are divided in to three categorize: side in take, front structure and bottom structure. According to the recent experiences at countries for maintain region, when longitude slope is more than 1% and 75% of bed load is particles with size more than of mm(D50>6mm) bottom in take are recommended generally. Hydraulic analyses of this type of structure are not studied numerically. In other side of Cain, building and studying physical model of this type of structure are very difficult tasks. In this research, flow simulations of bottom in take are done using  the flow 3D software. As a result, it's conducted that best Slope for intake net is degree and when opening area. Increased directed discharge increase directly. Finally it's driven that when froude number increased opening percentage,it May caused reduction of flow coefficient.