Enhancement of nonlinearity and parametric sonar using bubbles


Mantouka, A., Leighton, T.G. and Humphrey, V.F. (2007) Enhancement of nonlinearity and parametric sonar using bubbles. In, Papadakis, J.S. and Bjorno, L. (eds.) Proceedings of the Second International Conference on Underwater Acoustic Measurements, Technologies and Results. 2nd International Conference & Exhibition on "Underwater Acoustic Measurements: Technologies & Results" Southampton, UK, Institute of Sound and Vibration Research, 577-582.

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Description/Abstract

The potential of nonlinear pulsating bubbles to improve the performance of
parametric sonar has been known for some years, but exploitation of this phenomenon
and its theoretical modelling is still under investigation. This paper focuses on some
theoretical aspects of determining sonar parameters through modelling nonlinearly
pulsating gas bubbles in water. Existing expressions for these parameters were developed
when bubble theories had newly appeared, and since then they were not always been
updated with all the new modelling aspects. Without models, which encompass the
relevant physics, it is not possible to estimate sonar performance and its feasibility in
bubbly waters. For example, analytical formulae used today for the prediction of the
coefficient of nonlinearity are based on the Rayleigh equation, which later was improved
with damping effects. These formulae result in lower (and for some frequencies
unphysical) predictions for the coefficient of nonlinearity. Analytical formulae from this
work were used to estimate the parametric output. The sonar drive frequency was 920 kHz
and the difference frequency 50 kHz. Tank experiments were undertaken in fresh water
with low void gas bubbles to compare with this modelling approach.

Item Type: Book Section
Related URLs:
Keywords: nonlinear bubble pulsations, parametric sonar, coefficient of nonlinearity
Subjects: Q Science > Q Science (General)
T Technology > TA Engineering (General). Civil engineering (General)
Divisions: University Structure - Pre August 2011 > Institute of Sound and Vibration Research > Fluid Dynamics and Acoustics
ePrint ID: 49419
Date Deposited: 12 Nov 2007
Last Modified: 27 Mar 2014 18:32
Publisher: Institute of Sound and Vibration Research
URI: http://eprints.soton.ac.uk/id/eprint/49419

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