Numerical simulation of droplet coalescence based on the SPH method

In this paper, the smoothed particle hydrodynamics (SPH) method is employed in modeling and numerical simulation of droplet coalescence. Considering the effect of tangential force on boundary material, besides normal force, tangential force is also introduced in the continuum surface force (CSF) model. The formation of droplet, the coalescence processes of two droplets and three droplets are simulated by the modified CSF model. The validity of the modified model is verified from the aspects of the morphological change of the droplet, the smoothness of free surface and the conservation of the centroid of the system. Compared with finite element method, the results of the modified CSF model show that tangential force plays a crucial role in the CSF model when dealing with model boundary with curves and sharp angles.