Investigation of the flow characteristics of spherical harmonic particles using the level set method

Non-spherical granular flow is critical for hopper design and applications. Although particle morphology has an evident influence on the dynamic properties of granular materials, a large number of numerical simulations contribute to the dynamic behaviors of convex particles. In this work, concave particles are represented using the spherical harmonic functions, and the accurate collision forces between spherical harmonics particles are obtained by the level set algorithm. Subsequently, the influences of particle sphericity, shape parameters, and hopper angles on the mass flow rate, flow fluctuation, mass flow index, particle velocity, and inter-particle contact forces of spherical harmonics particles are investigated using the discrete element method. Results indicate that spherical harmonic particles with small sphericity and large shape parameters have dense clusters and strong interlocking, which cause larger normal contact forces between particles. As a result, spherical harmonic particles have lower flow rates and more significant flow fluctuations than spheres.