Research On Smoothed Particle Hydrodynamics And Its Application In Fluid-solid Two-phase Flows

Smoothed particle hydrodynamics is a classic meshless method,which has been widely used in the research of problems in fluid dynamics and solid dynamics.Boundary processing has always been a major concern among SPH researchers.For boundary containing complex geometry,like coastal engineering,floating structure,offshore drilling platform,etc,it is challenging to develop an accurate and efficient boundary processing method.In this work,the principle of SPH,discretement of N-S equations,and main steps in SPH algorithm are introduced.Several common solid boundary conditions are introduced then,including mirror bound-ary,dynamic boundary and dummy boundary.The advantage of mirror boundary has been numerically validated,especially for complex boundary.Some approaches to improving the global accuracy of mirror boundary are applied,including over-creation number and different initial distribution.The application of SPH in free-surface problems has also been studied,for instance,dam breaking,ball falling,bucket rotating,etc.Differences between wcSPH and ISPH have been investigated and numerical results indicate that our SPH simulator has good performance in scalability and practicability.Next,DEM and coupled DEM-SPH method are introduced Some important parameters like stiffness,timestep and particle ra-dius are decided through numerical experiments,which are crucial for numerical stability.Results from dambreak and bucket rotation indicate that current simulator is capable of simulating solid-fluid problems with comlex geometry or no-slip boundary,and numerical results are close to experimental ones.