Investigation Of SPH Neighborhood Search Algorithm And Its Application In Dam Break Simulation

Fluid simulation based on the SPH method determines the motion state of the whole problem domain through the motion of each particle,which is to solve the whole domain into a series of particles carrying a specific material property.However,in SPH method,the motion of all particles can be weighted by the motion properties of all particles within the support domain,and in each time step(the whole simulation time can be divided into several time steps),it is necessary to search the neighboring particles of each particle,so as to determine the moving property of the particle in the current time and the next time step.Therefore,the neighboring particle search algorithm plays a decisive role in the performance of the whole simulation process.In this paper,based on the existing neighborhood search algorithms,the neighborhood particle search algorithm is optimized from both algorithm and hardware to faster and more accurate search of neighboring particles.Firstly,this paper analyzes the present situation of fluid simulation and particle search algorithm,and briefly introduces how to discretize the Navier-Stokes equation by SPH method.And the research emphases and main work of this paper are established.Secondly,this paper introduces the common nearest neighbor search algorithms.The strip PIB search method and neighborhood correlation search method are introduced,and the specific implementation steps of the two search algorithms are described in detail in paper.And the advantages of the striped PIB search algorithm and neighborhood correlation search method are analyzed.In order to further improve the search efficiency of the neighboring particles in the SPH method,a new algorithm is proposed which uses the strip Point-In-Box(PIB)search method and the neighbor region correlation search method to alternate the execution mechanism to achieve search of neighborhood particles.The algorithm has been tested from search efficiency and search accuracy,and the feasibility of the algorithm is verified.Finally,combined with the high parallelism and programmability of graphics processor(GPU),the fusion search method is used to simulate the two-dimensional dam break fluid phenomenon by SPH method.In the experiment,the SPH method based on the fusion search method and the SPH method based on strip PIB search are used to simulate the dam break phenomenon.The experimental results show that the SPH method based on the fusion search algorithm enhances the simulation results of the complex structure and the details of the fluid.And under the condition that the number of particles is equal,the search efficiency of the fusion search method based on GPU is higher several times than the efficiency of the fusion search method based on CPU and the search method of multidimensional tree based on GPU,further illustrate the high efficiency of the improved algorithm.