Tomographic reconstruction of shallow water bubble fields

Author

Rouseff, Daniel ; Henyey, Frank S. ; Caruthers, Jerald W. ; Stanic, Stephen J.

Author_Institution

Appl. Phys. Lab., Washington Univ., Seattle, WA, USA

Volume

26

Issue

1

fYear

2001

fDate

1/1/2001 12:00:00 AM

Firstpage

131

Lastpage

140

Abstract

In March of 1997, a shallow water experiment was conducted near the Scripps Pier in La Jolla, CA, USA. The goal was to determine the dynamics, distribution, and acoustic effects of bubbles just offshore from active surf. A major component of the experiment was the “Delta Frame”, an apparatus that supported two acoustic sources and eight receivers. Acoustic intensity was measured at frequencies between 39 and 244 kHz over the resulting 16 horizontal ray paths. Paths ranged in length from 2.5 to 8.6 m. In the present paper, a tomography algorithm is developed and implemented using Delta Frame data. Measurements are combined to produce quantitative cross-sectional images of the attenuation associated with the bubble cloud. Numerical simulations predict that the Frame ran resolve details of the field down to about 2 m. Images constructed at different acoustic frequencies are scaled and compared. A 5-min sequence of images is studied in detail. Swell waves are shown to cause rapid fluctuations in the images

Keywords

acoustic intensity; acoustic tomography; bubbles; image reconstruction; numerical analysis; time series; underwater acoustic propagation; 2 m; 2.5 to 8.6 m; 39 and 244 kHz; 39 to 244 kHz; 5 min; 5-min sequence; Delta Frame; Swell waves; acoustic effects; acoustic intensity; bubbles; distribution; dynamics; fluctuations; horizontal ray paths; length 2.5 to 8.6 m; numerical simulation; quantitative cross-sectional images; shallow water bubble fields; shallow water experiment; tomographic reconstruction; tomography algorithm; Acoustic measurements; Acoustic propagation; Acoustic refraction; Attenuation; Clouds; Frequency; Oceans; Sea measurements; Tomography; Underwater acoustics;

fLanguage

English

Journal_Title

Oceanic Engineering, IEEE Journal of

Publisher

ieee

ISSN

0364-9059

Type

jour

DOI

10.1109/48.917949

Filename

917949