Research And Application On Two-Dimensional Numerical Simulation Of Flows With Complex Boundaries

The research and application of two-dimensional horizontal shallow water model have been a long history, and many research results about it have been applied to actual engineering, such as water conservancy, environment, port and channel, flood defense, and etc; and play an important guidance role in the organization, continuous development and utilizations of water resources. Because the natural streams are serpentine, narrow and long, the commonly-used two-dimensional depth-averaged model couldn' t accurately predict bend flows with the obvious 3D properties. So in this thesis, a curvilinear gird being orthogonal near the boundaries has been generated by using a proposed boundary-fitted coordinate technology; and by modifying the two-dimensional horizontal shallow water model in curvilinear coordinate system, the flow fields with complex boundaries can be obtained. The research details of this paper are as follows:(l)To overcome difficulties of numerical simulation resulting from complex boundary, the boundary-fitted coordinate technology is used. At the same time, aiming at some problems concerning the adjusting functions in the commonly used Thompson and Thomas methods in the generation ofcurvilinear grid, a new adjusting function is proposed, by which the curvilinear gird being orthogonal near the boundaries can be generated.(2)The commonly used two-dimensional horizontal shallow model has been corrected in considering the transverse momentum exchange caused by the secondary flow in bends.(3)The governing equations of the correction shallow water model have been split into two groups of equations by Yanenko method; and then each group of those have been solved by the alternating-direction-itnplicit technique. Upwind scheme is used and pervasion item is thank about in the course of discretization equations.(4)By using the correction shallow water model in curvilinear coordinate system, the behaviors of the flows through the curved channel with an angle of 90° in front of the sluice gate, and of the flows in a sequent bends have been computed; And the computational results of the two examples coincide well with the measured data. At last, the flow behaviors of water supply pool in front of TianShi pumping station under different operating conditions have been predicted to demonstrate the reasonability of the modified scheme of TianShi pumping station.The research results in this dissertation have provided a good basis for research of sediment and water quality in river flows and river seashore engineering.