Conference_programme: 19: Sound propagation
Lecture: Measuring sound extinction of bubble clouds in a water tank
Author(s): Raveau Maria Paz
Summary:
The primary purpose of this work was to investigate the applicability of sound attenuation models trough dense bubble clouds, when multiple scattering between bubbles can not be neglected. For this purpose, a 4x6x0.8m wooden test tank was waterproofed and filled with fresh water, and a 25cm by 25cm grid was marked on the tank floor. Using comercial aquarium air pumps and air walls, close-packed bubble clusters of around 3000 bubbles were generated, where the mean bubble radius was estimated in 1mm. Using a dual FFT tool, the transfer function was measured in various locations, with and without bubbles. A steady state subtraction method was used in order to isolate the effect of the bubbles in the sound pressure field inside the tank [J. Acoust. Soc. Am., 112, 1366-1376 (2002)]. Several acoustic variables were obtained from these measurements, like the insertion loss, the scattered pressure and the extinction cross section. The experimental results were compared with available attenuation theories, including an existing predictive model used previously to study collective back scattering from schools of swim bladder fish, which incorporates both multiple scattering effects among the bubbles, and coherent interactions of their individual scattered fields [J. Acoust. Soc. Am., 99, 196-208 (1996)]. Computational modeling, experimental details and data/model comparison are presented.
Corresponding author
Name: Dr Maria Paz Raveau
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Country: Chile
