### ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

## 5aPAb13. A study of the natural frequencies of spherical and distorted
bubbles in open cavities.

**Andrea Prosperetti
**

**
Hasan N. Oguz
**

**
Jun Zeng
**

**
**
*Dept. of Mech. Eng., Johns Hopkins Univ., Baltimore, MD 21218
*

*
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The natural frequency of a bubble in an open, liquid-filled cavity is
studied. A number of axisymmetric and three-dimensional configurations are
considered such as a bubble in a cylindrical tube closed or open at one end and
open at the other, a bubble between two parallel plates, a bubble in an open
spherical cavity, and others. For bubbles that are smaller than the acoustic
wavelength, the incompressible potential flow approximation is adequate. The
natural frequency is computed by a boundary integral method. A slightly
overexpanded bubble is allowed to relax and oscillate, and its frequency is
measured by taking the Fourier transform of the volume pulsations. Alternately,
a constant potential over the bubble surface is imposed and the natural
frequency is calculated from the resulting volume flow rate of the bubble. These
two techniques give nearly identical results for linear oscillations. For each
geometry, spherical as well as distorted bubbles are investigated. [Work
supported by the Office of Naval Research.]