Consideration on the holding force in near field acoustic levitation

摘要

In the near-field acoustic levitation, the lateral position of the levitated object is automatically maintained by 'holding force,' which acts on the object so as to minimize the lateral displacement. The authors discuss, in this report, on the simulation of the holding force under the assumption that the force is generated by the acoustic streaming induced in the gap between the vibrator and the object. First, the acoustic streaming is observed by a video camera to confirm the relationship between the streaming and the holding force. Next, the calculation model is examined for precise prediction of the acoustic pressure field. The report concludes that the quantitative value of the holding force can be calculated for different vibration modes if the coefficient of the calculation is once decided experimentally.