ACOUSTIC CAVITATION AND BUBBLE INSTABILITIES.
NAVY MINE DEFENSE LAB PANAMA CITY FLA
Pagination or Media Count:
The nonlinear differential equation of undamped motion for a bubble under the influence of a sinusoidal pressure field in an infinite incompressible liquid is examined for instabilities by the small perturbation method. The purpose of the investigation is to experimentally determine if acoustic cavitation occurs at lower acoustic pressure at the predicted instability frequencies of the nonlinear equation for bubble motion. An acoustic cell with a plate glass top was designed and built in which bubbles were trapped against the underside of the horizontal glass. The effect of the glass boundary was calculated. The effect of the boundary changed one term in the nonlinear differential equation by a constant which lowered the resonant frequency of the bubble. The resonant frequency for an air bubble trapped against the glass of the acoustic cell was measured and found to be in close agreement with that predicted. Measurements also showed that for an air bubble in water acoustic cavitation will occur at lower acoustic pressures at the bubbles resonant frequency and possibly at the second harmonic. There was no indication of subharmonic effects for the air bubbles in water. Author
- Fluid Mechanics