Numerical Model For Circumfluence And Movement Of Sediment In Continuous Meandering River

The natural channel can be seen composed by a series of bends and straight reaches. So, the study for the movement of water and sediment in the ideal bend can be seen as the basis in the natural channel. The traditional method is building a physical model in a certain scale and doing experiments. Though this method has many strongpoint of its own, but it still has many shortages. With the development of the computer technique, as one important method in the channel simulation field, it is applied and developed more and more. For the special boundary condition and geometry profile of meandering river, when water going into together with sediment, the former character will change, such as the superelevation of water surface and the difference of pressure in the centripetal direction. For these changes, the water in the meandering river will bring the movement of circulation. For the whole water, the special movement is the spiral flow. The sediment in the meandering will bring lateral moving because the transverse circulation. So the sediment of concave bank will be scoured and deposited in the convex bank. In the continuous meandering channel, the two different modes of sediment are the movement of same bank and different bank. In this paper, the movement phenomena of water, the transporation law of sediment, there is a particular discussion for the distribution of bed shear, the pick-up velocity of sediment and the sediment discharge in the meandering river. In this paper, the main method that is the numerical method and the experiment of physical model are used to simulate the circulation flow. After simulation, the effect by the circulation flow to the transporation of sediment is analysed in this paper. To choose the model suit for the simulation, many researching result of the former researches is discussed and used for reference in this paper, and at last the κ~ εmodel combined with VOF and Eulerian model is chose to do the numerical simulation work. At first, the velocity which is the outlet velocity of 2-D numerical model by using the VOF and κ~ εmodel is used as the inlet velocity of the 3-D numerical model. The control equations of 3-D water and sediment movement are described in the orthogonal curvilinear coordinates, and the equations is segregated by using the Finite Volume Method (FVM). The SIMPLE algorithm was adopted in the numerical program. For the control with the result of numerical simulation, the same size with numerical method model is used in the physical experiment. The result of physical experiment shows that the movement and evolvement of circulation flow accord with the result of numerical simulation. It is the same for the result of scouring and sedimentation.