A Simplified Model for the Normal Collision of Arbitrary Shape Particles in a Viscous Flow

Modeling collision of finite size arbitrarily shaped particles is a tedious task because of difficulties in finding the collision parameter for the non-spherical particles. These parameters include the contact point, direction of the collision force and the collision forces and moments. In this paper a new collision algorithm is proposed to simulate collision of arbitrary shape particles to tackle flows containing a large number of particles. A pseudo-potential function is defined to quantify the collision parameters. This potential is defined based on the distance from the particle interface using either level set method or an analytical representation. With this definition, we can find the direction of collision forces and the amount of overlapping during the collision course. The collision forces are applied through a spring with a coefficient defined based on the collision course. In order to apply the damping, after the maximum collision course is achieved a spring with a lower stiffness in devised to achieve the desired bounce velocity. The results are validated for a spherical particle colliding with a wall. Then we show the capability of the model in simulation of collision of non-spherical particles with a wall. The new collision method not only is simple to implement but also it is applicable for any particle shape.