Research On Algorithm Of Moving Particle Semi-implicit Method

When ships are navigating in heavy seas, it's inevitable to face rough water. Usually, it will cause very serious nonlinear oscillation Because of relative motion between ship and wave is very large, it has the problem of shipping water that the water level exceeds the bow height and water rushes on the deck and also impacts the bow. Based on there are so many difficulties with large deformed and numerical incontinuous problems in mesh method, this study introduces a meshless method-Moving Particle Semi-implicit Method among various numerical methods. It based on a fully Lagrangian description. Numerical diffusion doesn't arise because convention terms are not discretized. Differential operators in governing equations are transformed to equivalent particle interactions using a weight function. This method contains character of fluid particles which can move with reciprocity of external and inner forces and more convenient and flexible in simulating very serious nonlinear free surface flow. In theory, it can deal with all kinds of transformative flow and easily implement. In each time step, A semi-implicit algorithm is used to solve momentum equation, all terms are explicitly calculated except pressure term. MPS was applied in the nuclear field at first, it is a new approach in the field of hydrodynamics and at the stage of theoretical research at present.This paper is focused on the further investigation on the basic theory of MPS Method, and prepares for wide application in the fields of shipbuilding and ocean engineering. For this reason, the following problems are emphatically investigated.Firstly, this paper introduces the basic theory and developmental history of mesh and meshless method, and also introduces the present situation of MPS method.Secondly, the algorithm of MPS is researched and the common kernel functions are presented. The discretized model of differential operators in governing equations are analysed, and the incompressible idea and calculation algorithm of MPS are introduced in this paper.At last, 2D flow between two infinite plates is simulated with treatment of inflow and outflow boundary. On the one hand the precision of the algorithm can be validated, and on the other hand the regular of the algorithm can be mastered. This is the basic progress of the further work. Furthermore, this paper also simulates typical free surface flow- the collapse of water column, and compares the influence of boundary condition, formulation of displacement, time step, iterative method, kernel function and initial particle spacing.