The Two-dimensional Simulation On The Diffusion Of Emulsified Oil In The Tide Sect Of The Yangtse River

Currently,the water area which the large tonnage watercraft pass in and out will have the most risk of oil spill accidents .The probability of the risk bears on the density of the craft traffic,the status of the water area,the climate condition , the level of the technology and manage, and so on. The Yangtse River ,which is the most important river in our country ,arouse the right effect in the development of our community economy .With the development of traffic in the river,setting up the emergency system about the oil spill accidents is pressure and necessary. Then, numerical model ,to simulate the occurance and harm of the accident ,is the core part of it.Due to the behavior and character of the oil spilling into the water, the simulation mainly includes two sections :at the beginning ,oil film move on the surface of the water. The spreading and excursion model will be used to express the bound and locus of oil film;Then ,with disturbing of the strong hydraulics and other factors ,oil film break up,and form oiliness sewage,distributing on the y coordinate .The quality model will be used to simulate the oil strength extension.The model is used in front of the coal dock of the ChangShu in the Yangtse River. A depth-averaged two dimensional unsteady flow equation is developed to describe water flow, and two-dimensional convection-diffusion equation to describe the diffusion of emulsified oil. A two-dimensional water quantity and water quality coupling model using finite volume method (FVM) is established to simulate water flow and the diffusion of emulsified oil. Flux difference splitting (Osher) algorithm, an approximate Riemann solver, is employed to estimate the normal fluxes across the interface of cells. The two-dimension simulation is transferred into solving a series of local one-dimension problem, which is used to simulate the hydrodynamic process and oil pollution diffusion.The model is applied to the simulation of the movement of water flow and the diffusion of oiliness water on The Yangtse River,analyzing the connection of the surface velocity and the wind velocity. The result can be used in predicting the diffusion of oiliness wastewater on The Yangtse River and other large water body. It also provides theoretical base and technical method for the establishment of the mathematics model on shallow waters, or the outburst of the Oil Spill Emergency Prediction System.