Numerical modeling of turbid density current in Dez Reservoir, Iran

摘要

The turbidity currents, which enters the reservoirs of dams through the increase in suspended sediment concentrations in river flows during flood events, is one of the most significant element in sedimentation of dam reservoirs. The process decreases water capacity of reservoirs and dams life time. Opening of sluice gates is a common method for the evacuation of sediment. During the operation, being well-informed of manner of movement, distribution, longitudinal, transverse and deep expansion of these currents as well as their arrival time to the dam body, plays an important role in optimal time management of the gates opening and closing However, optimal opening and closing of gates requires accurate information about the density current in the reservoir. In this paper, the evolution of density current in the reservoir of the Dez Dam in Iran is simulated using a CFD code and the numerical results are compared with field measurements. The results show turbid density current has been reached 22 kilometer distance to the dam wall with flood discharge 1663 m^3/s and input concentration 5000 mg/1 in during 30 hours.