Modeling near Field Acoustic Levitation by Flexural Mode including Gas Inertia

We report a combined theoretical and experimental investigation on the near field acoustic levitation (NFAL). In NFAL a disk is levitated at a height much smaller than the acoustic wavelength. The levitation force is induced by the gas squeeze film between the sound radiation surface and the levitated disk. By taking into account the flexural vibration of the sound radiation surface as well as the gas inertia effect, a modified Reynolds equation has been developed. A high-order finite difference scheme was used to numerically solve the nonlinear convection-diffusion equations. The numerical results and the experimental observations show excellent agreement.