With some popular tracking methods for free surface, simulations of several typical examples are carried out under various flow field conditions.The results show that the Smoothed Particle Hydrodynamics (SPH) method is very suitable in simulating the flow problems with a free surface.A viscous liquid droplet with an initial velocity impacting on a solid surface is simulated based on the SPH method, and the surface tension is considered by searching the free surface particles, the initial impact effect is considered by using the artificial viscosity method, boundary virtual particles and image virtual particles are introduced to deal with the boundary problem, and the boundary defect can be identified quite well.The comparisons of simulated results and experimental photographs show that the SPH method can not only exactly simulate the spreading process and the rebound process of a liquid droplet impacting on a solid surface but also accurately track the free surface particles, simulate the free-surface flow and determine the shape of the free surface due to its particle nature.
LI Da-mingXU Ya-nanLI Ling-lingLU Hui-jiaoBAI Ling
This paper uses the Oseen transformation to solve the differential equations governing motion of the vertical linear gradient flow distribution close to a wall surface.The Navier-Stokes equations are used to consider the inertia term along the flow direction.A novel contour integral method is used to solve the complex Airy function. The boundary conditions of linear gradient flow distribution for finite problems are determined. The vorticity function, the pressure function, and the turbulent velocity profiles are provided,and the stability of particle trajectories is studied. An Lx-function form of the third derivative circulation is used to to simplify the solution. Theoretical results are compared with the experimental measurements with satisfactory agreement.
