What we have: Supposed that we have a loudspeaker-based ultrasonic levitator. including a low voltage sine wave generator, an amplifier and a loudspeaker + a metal plate and some clamp-stands +some small polystyrene balls to levitate.

Main idea: This levitator is designed to work at a frequency (or pitch) of around 25 kHz which is above the audible range of humans.

How can we determine how much will be the movement of small polystyrene balls?

• The sine wave generator, generates a sine wave in the frequency range 20-30 kHz and an amplitude in the range 1-5 Volts (peak-to-peak).
• The amplifier: 100 Watts, able to amplify old fashioned analogue signals.
• The load speaker: high power tweeter or compression horn tweeter that works fine up to 30 kHz.
• The object: small polystyrene balls with the range 1-2 mm.
• Distance of plate and speaker: 50 mm.

This is very important that the exact movement of matters determined by mathematical formula.

• How can we determine how much will be the movement of small polystyrene balls? .... experimentally
– jsotola
Jan 22, 2018 at 20:35
• Thanks @jsotola , but this experiments can't repeat for each different value or the high range generators; so we decided to have a brain storm to find an equation for this problem.
– SM_SOF
Jan 22, 2018 at 20:39
• @SM_SOF How do you intended to verify your equation if you can't develop a repeatable experiment?
– vofa
Jan 22, 2018 at 20:42
• This seems to be more of a physics question. You do not give details on the generated field, but is seems to be a simple standing wave. For speed of sound 331,2 m/s and 25kHz, nodes are 13.2 mm apart, that's simply a division (speed divided by frequency).
– Andreas
Jan 22, 2018 at 21:05
• Maybe some sort of stroboscope in-phase with the speaker but with variable offset. The strobe should flash in combination with a video camera running at e.g. 120 FPS. Thus it flashes once for each video frame, but still with know phase from speaker.
– oldfart
Jan 22, 2018 at 21:10