Study On The Numerical Simulation Of Unsteady Density Current

The production of density current often gives birth to the loss of reservoir capacity and river silting. But it also has some good use, it provides a new approach of removing sediment for Reservoirs.Accordingly, the study of density current has great practical value.Density current operation is an important way to remove sediment of reservoir especially the reservoir in the earlier phase. In order to optimize the density current operation, we must control the routing of density current to minimize the loss of water and remove sediment.The previous calculation of density current routing is just use experience formula. But the result is not very satisfying.The unsteady density current numerical model is put forward on the basis of the density current theory studied resent years.The model used the assumptive flowing method, record the position of the density current's front. It can calculate the routing current of density current.The dissertation take the Xiaolangdi reservoir in the sixth experiment of regulating water and sediment as an example, set a numerical model to simulate the routing of xiaolangdi reservoir'density current. It brings the concept of outlets flowing into this model and it can also used in the calculating of sediments removed by density current.Comparing with other density current model, it needs less information and calculate more efficient. The dissertation calculates the salt intrusion of Nandu River by the opposing slope density current model which considers the velocity of upper flow. The model generalizes the configuration of the salt water wedge, and calculates the variety of the distance of salt intrusion in different river flux. Finally, it concludes the regularity of salt intrusion.The analysis of calculation result proves that the two models in the dissertation are efficient. The study results provide a new way for simulating density current'routing and a technique basis for the engineering problem.