CFD Application in 3D Flow Filed Modeling of Large Dam Reservoir

In the present paper, a 3D numerical model has been applied to predict the flow hydrodynamics around power intakes within the Dez dam reservoir. The Dez dam is a203 m high, double arch concrete dam which is constructed by Italians in 1962. Since then, sedimentation in reservoir has continued and since the dam does not have bottomoutlet, the reservoir bed level is raising by a rate of about 2.5 meter per year. The power intake invert level is in 270 m asl and on the basis of 2007 hydrography results, thereservoir bed level has reached the level of 260 m asl that means the sediment level is just10 meters below the power tunnel intakes. The applied three-dimensional model is a finite volume model, which can model curvilinear and non-orthogonal domains and uses thefully 3D time averaged Navier Stocks equations. For incorporating the effects of turbulentflow in computations, an advanced turbulent model, named k -w model has been applied. The present model results for flow field around power intakes show that for thepresent conditions (sediment level of 260 m and intakes level of 270 m ) some limited amount of sediments is entering power tunnels and if no rehabilitation measures isconsidered, more sediment will enter the power tunnels in the coming years

Keywords:

3D numerical model , dam reservoir , sedimentation , k-w turbulence model