The Numerical Simulation Of Stepped Spillway Based On Smoothed Particle Hydrodynamics(SPH) Methoed

The stepped spillway is a new form of spillway which has high energy dissipation rate. Due to its special shape and significant energy dissipation efficiency, many engineerings regard stepped spillway as alternatives, which are widely adopted now. The large deformation of free surface and the broken water flow are the main difficult points in the research of stepped spillway, which are easy to be solved by use of the SPH (Smoothed Particle Hydrodynamics) method.Therefore, the SPH method is adopted to simulate the stepped spillway in this dissertation, which also use the method of the combination of model tests and numerical simulation to study the stepped spillway flow regime, pressure, water surface, velocity, cavity of step and energy dissipation effect. Great significance of the development and application of stepped spillway has been made by this research.The main contents of this dissertation are as follows:1. An introduction of theoretical basis of SPH method are very detailed.In this method, Two forms of basic equations of SPH form are derived, including integral representation and particle approximation.2. Due to the modification of SPH code, Arbitrary two-dimensional model can be constructed by use of data points, which also solves the problem of particle redundancy and greatly reduces the number of particles. A parallel SPH method is used meanwhile, which improves the computational efficiency.3. A method is found out to solve the problem of outflow in the numerical simulation.Three kinds of models are proposed to solve the problem of constant inflow:1) Large water tank model. We find that the layout plan of this model is easy by setting the outflow experiment of orifice nozzle, which can be adopted in the numerical simulation of small water head, short simulation time and low computational accuracy in the field of hydrodynamics.2) Two water tank model. The numerical simulation of the model is carried out by using SPH method, and the results are analyzed.3) Model of pushing plate. The results of numerical simulation show that the model to solve the problem of constant flow is satisfactory. By setting different velocity and with the same water depth, the model of pushing plate is used to study the relationships among the velocity of pushing plate, water depth and flow, which also indicates the model of pushing plate is applicable in the field of hydrodynamics.4. The numerical simulation of stepped spillway shows many phenomena, including water flip, splashing phenomenon, phenomenon of water mixing and back to the vortex, which also calculate the pressure of steps and distribution of water depth and flow. Advantage of solving the problems of large deformation of free surface by use of SPH method has been proved. The compare of experiment results and numerical simulation results is carried out in detail.