The Sedimentation Deformation Calculation By Quasi-2D Numerical Simulation In The Qingtongxia Reservoir

Qingtongxia reservoir is a daily reservoir in the main river of Yellow river, which is chief function of irrigation, and intergrated generate electricity, flood control, ice prevention, and municipal water supply, and so on. By more than forty years management, at present, it reaches a state of silt stable. The reservoir sedimentation deposit carries a series of problems for the normal management and generating electricity of reservoir, as the flood control capability depress and irrigation capability fall, enhancing the turning on force of water sluice gate. Those are badly impact the normal management and flood control security.In the paper, through analyzing the Qingtongxia reservoir present state of silt and feasure of erosion and deposition, and againsting at the concretely circumstances, set ups a quasi-2D unsteady nonuniform model basing on the 1-D unsteady model, and using the model investigates the Qingtongxia sediment problems.When sets up the model, following flow direction of channel, divded sereval stream tudes, and using the noncoupling method solved the flow and sediment equation. When calculated the flow equation, is varianced by preissmann four-point-eccentricity difference scheme, and evaluation the solution with purisuit method. The non-equilibrium transportion equation of suspended load is varianced by aweather format, then it becomes difference equation and is slvoed. During caculating according the feature of model ,select the proper equation of sediment carry capacity, suspended load gradation and sediment fall velocity, as well as ,unsaturated coefficient, roughness,and so on. Divided sediment mixture into several size groups, counts the grouping sediment deformation in every stream tube. Finaly utilizing the theory of minimum rate of energy dissipaton judge how about distribute the sediment deformation neighour sidebanks stream tubes, thereby, ascertain changeable river width.By analyzing the measured water sand data of Qingtongxia reservoir, select the end of flood season of 2004 measured datas, veriflies the model of paper ,the result is satisfactory. Using the model investigates the rules of the reservoir erosion and deposition, as well as analyses the relation of storing clear and releasing muddy handle manner and the course of erosion and depositon. - ii -...