Principle of the rotation of small particles around a nodal point of flexurally vibrating strip

In this report, we investigate the principle of rotation of micro particles around a nodal point of metal strip in flexural vibration, by experimental measurement and theoretical analysis. It is experimentally found that travelling wave may exist along the circles centered at the nodal point, and the travelling wave can drive a particle cluster agglomerated at the nodal point to rotate. The acoustic radiation force, acoustic viscous force and acoustic streaming are excluded from the possible driving force by measuring and comparing the revolution speed of particle cluster in the normal environment of 1 atm and 25°C and in a glass vessel of 0.04 atm and 25°C. The physical principle obtained can well explain the measured relationships between the revolution speed and vibration displacement amplitude. Also, it is found that there is slide between the rotating particles and vibrating surface.