A standing wave acoustic levitation system for large planar objects

摘要

An acoustic levitation system is presented which can levitate planar objects that are much larger than the wavelength of the applied acoustic wave. It uses standing wave field formed by the sound radiator and the levitated planar object. An experimental setup is developed, by which a compact disc is successfully levitated at frequency of 19 kHz and input power of 40 W. The sound field is modeled according to acoustic theory. The mean excess pressure experienced by the levitated object is calculated and compared with experiment results. The influences of the nonlinear effects within the acoustic near-field are discussed. Nonlinear absorption coefficient is introduced into the linear model to give a more precise description of the system. The levitation force is calculated for different levitation distances and driving frequencies. The calculation results show acceptable agreement with the measurement results.