Unified Particle Method Research For Simulation Of Landslides Generated Waves In Reservoir Bank

The problem of landslides generated waves caused by the instability of the reservoir slope can be regarded as a multiphase flow problem mainly composed of rock landslides body,water and air.The numerical calculation of this problem is extremely complicated.With the development of relevant theories and application work in this area,the limitations of existing analytical methods are becoming more and more prominent,and there is an urgent need to develop new alternative methods to solve the problem of computational difficulties of such fluid-solid coupling.In this paper,after research and analysis on the relevant research progress and results of landslide surge,the fluid-solid coupling model and algorithm of unified particle method are constructed,and the coupling processing of fluid and solid under the same framework is realized.The whole process of landslides generated waves caused by slope instability is simulated and analyzed,which provides comprehensive and accurate data for the dynamic evolution of virtual and real fusion.This will provide guidance for better assessing,controlling and managing the risks of hazards such as landslides generated waves in real-world environments.The main work of this paper is as follows:(1)The research status of the fluid-solid coupling simulation in landslides generated waves is analyzed in detail,and the framework for implementing the basic particle method is selected.It involves the investigation of fluid-solid interactive evolution simulation techniques.Some methods include improving computational efficiency,ensuring uniform distribution of fluid density and pressure at the solid-fluid interface,and preventing fluid particles from passing through a solid boundary.The open source framework implements the basic weakly compressible smoothed particle hydrodynamics theoretical model based on graphics processing unit,is finally determined as the basic framework of this paper.(2)A method of reducing the density fluctuation of weakly compressible fluids is implemented under the basic framework.It involves the addition of the Laplacian of the density field to the continuity equation under the basic weakly compressible smoothed particle hydrodynamics theoretical model framework.This makes it possible to avoid the problem of particle penetration,large gaps between boundary particles and fluid particles,and non-physical high pressure values at boundary particles when simulating a large deformation flow of a free surface.(3)The problem of particle homogenization placement for the pre-processing stage of numerical calculation is studied.Specifically,it involves the discrete work of combining the vertical and horizontal equidistant segmentation and grid topology optimization techniques.It includes the discretization of the simple area of the rule and the irregular complex area,and compares the method proposed in this paper with the commonly used methods by numerical examples.(4)The coupling calculation problem between rigid body and fluid is studied.It involves the combination of weakly compressible smoothed particle hydrodynamics and discrete element particle method to establish a unified particle model for dealing with the interaction between discrete blocks and fluids.It is possible to discretize solid structures of any shape and to simulate the dynamics of solid-fluid interactions with 6 degrees of freedom in a two-phase flow.(5)Research work on coupling calculation problems between non-Newtonian fluids and Newtonian fluids.Specifically,based on the weakly compressible smoothed particle hydrodynamics,combined with the Shields criterion,the Drucker-Prager yield criterion and the suspension layer mechanics model,the numerical model of the two-phase flow model for simulating the landslide generated waves of fine rock and soil is established.(6)Combined with the physical experiments in the literature,the proposed theoretical model is validated and analyzed,and finally the research results are applied to the simulation of actual landslides generated waves event.Specifically,it includes the relationship between theoretical model simulation values,experimental and field data estimates,and involves experimental design,data processing and comparative analysis.The main innovations of this paper are: 1)Introducing a diffusion term in the continuity equation to reduce the density fluctuation of weakly compressible fluids;2)Proposing a method for homogenizing particles in the pre-processing process of particle method calculation for improving the stability and accuracy of the calculation;3)A unified particle model combining weakly compressible smoothed particle hydrodynamics and discrete element particle method is established to solve the simulation of block landslide generated waves;4)A two-phase numerical model based on weakly compressible smoothed particle hydrodynamics is established to solve the problem of non-Newtonian fluid and Newtonian fluid coupling calculation,which is used to deal with the calculation of a large number of fine rock and soil landslides generated waves;5)Applying the calculation model of landslides generated waves of fine rock and soil to the simulation of the Huangping landslides generated waves event in Yunnan in 2013,the accurate wave height and the complete landslides generated waves process are obtained.This provides more comprehensive and relatively accurate data for the dynamic evolution of virtual and real fusion.This paper has carried out some explorations on the numerical simulation method and its implementation in the large-scale structural evolution and solid-fluid interaction simulation in the landslides generated waves of reservoir bank,and hopes to provide valuable reference for designers or researchers.