Artificial bubble cloud targets for underwater acoustic remote sensing

Journal article

This article describes a technique that uses polymer additives to suspend air bubbles to form stable artificial bubble clouds. The results presented include the range of polymer concentrations for an effective bubble suspension; the void fraction, bubble size distribution, and stability of the generated artificial bubble clouds; and the effects of polymer on the acoustic properties of the bubble clouds, especially the acoustic velocity. It is concluded that, for low-frequency applications (less than 1 kHz), polymer concentrations of less than 1% do not modify significantly the acoustic velocity of bubble clouds. The stability of the produced bubble clouds can be made to last from a few hours to days or even months depending on the polymer concentration and the bubble size. Because only a low polymer concentration and small void fraction (both less than 1%) are needed to generate effective scattering, the density of the produced bubble cloud target and its response to hydrostatic pressure are similar to those of the ambient sea water; thus, adjustment to quasi-neutral buoyancy is not difficult. These results suggest that underwater acoustic targets and quasi-neutrally buoyant tracers that are small but have large acoustic cross sections can be produced with artificial bubble clouds suspended and stabilized by polymers.

Authors: Hwang, P; Roy, R; Crum, L

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Meteorological Society
• Journal: Journal of Atmospheric and Oceanic Technology
• Volume: 12
• Issue: 6
• Pages: 1287-1302
• Publication date: 1995-12-01
• DOI: 10.1175/1520-0426(1995)012<1287:abctfu>2.0.co;2
• EISSN: 1520-0426
• ISSN: 0739-0572
• Language: English
• Keywords: SBTMR