Analysis of levitation force acting on cylinder with hole placed between vibrating surface and plane

Abstract When a vibrating surface is placed above a cylinder with a through-hole in its center that is placed on a flat base, the cylinder is levitated. In this study, the levitation principle is investigated by analyzing the forces acting on the cylinder. It is found that the intense sound pressure that forms between the vibrating surface and the top of the cylinder pushes the cylinder down and prevents it from levitating. Under the assumption that there is a tiny gap at the bottom of the cylinder, the effects of the shape of the cavity at the bottom of the cylinder on the levitation force are investigated using finite element analysis (FEA). The results show that under certain conditions, the acoustic radiation force and the levitation force increase due to the acoustic streaming generated at the bottom of the cylinder. The results of the levitation experiments and observations of actual acoustic streaming show good agreement with the FEA results.