A model for the horizontal directionality of breaking wave noise in the surf zone

A model is presented for the horizontal directionality of the noise generated by individual breaking waves in the surf zone. The model is based on the interaction between sound radiated by ringing bubbles created in a breaking wave crest and the population of acoustically quiescent bubbles left on the seaward side of the wave in the shallow water waveguide. The effect of the quiescent bubbles is to absorb sound from all but the very ends of the breaking crest, resulting in the formation of "acoustic hot-spots." The model calculations are in good agreement with observations of the horizontal directionality of noise from individual breaking waves in the surf zone.

[1]  H. Cox.  Spatial correlation in arbitrary noise fields with application to ambient sea noise , 1973 .

[2]  R. M. Hamson.  The theoretical responses of vertical and horizontal line arrays to wind‐induced noise in shallow water , 1985 .

[3]  Angle–time–frequency resolution of the noise field generated by wind‐induced breaking waves , 1996 .

[4]  A. Prosperetti,et al.  Coherent and incoherent scattering by oceanic bubbles , 1993 .

[5]  W. Kuperman,et al.  Spatial correlation of surface generated noise in a stratified ocean , 1980 .

[6]  Grant B. Deane,et al.  Acoustic hot-spots and breaking wave noise in the surf zone , 1997 .

[7]  Herman Medwin,et al.  Bubble sources of the Knudsen sea noise spectra , 1989 .

[8]  Mark J. Beran,et al.  Combined volume and surface scattering in a channel using a modal formulation , 1995 .

[9]  Effect of random sea surface and bottom roughness on propagation in shallow water , 1995 .

[10]  A. Prosperetti,et al.  Backscattering of underwater noise by bubble clouds , 1993 .

[11]  Andrea Prosperetti,et al.  Bubble‐related ambient noise in the ocean , 1985 .

[12]  A. E. Hay,et al.  Ambient noise in the natural surf zone: wave-breaking frequencies , 1997 .

[13]  M. Buckingham.  A theoretical model of ambient noise in a low‐loss, shallow water channel , 1980 .

[14]  C. Harrison.  Noise directionality for surface sources in range-dependent environments , 1997 .

[15]  C. Harrison.  Formulas for ambient noise level and coherence , 1996 .

[16]  R. M. Hamson.  Vertical array response to shipping noise: Model/measurement comparisons for range‐dependent Mediterranean sites , 1993 .

[17]  Guy V. Norton,et al.  The effect of sea-surface roughness on shallow water waveguide propagation: A coherent approach , 1996 .

[18]  C. H. Sherman,et al.  Addendum: Spatial‐Correlation Functions for Various Noise Models [J. Acoust. Soc. Am. 34, 1732–1736 (1962)] , 1965 .

[19]  Herman Medwin,et al.  Acoustical measurements of bubble production by spilling breakers , 1990 .

[20]  Andrea Prosperetti,et al.  Active and passive acoustic behavior of bubble clouds at the ocean’s surface , 1993 .

[21]  Mark R. Loewen,et al.  A model of the sound generated by breaking waves , 1991 .

[22]  D. H. Peregrine,et al.  Breaking Waves on Beaches , 1983 .

[23]  G. Deane.  Sound generation and air entrainment by breaking waves in the surf zone , 1997 .

[24]  Eric Lamarre,et al.  Void-fraction measurements and sound-speed fields in bubble plumes generated by breaking waves , 1994 .

[25]  Spatial coherence of wind‐generated noise in a shallow ocean channel , 1981 .

[26]  Dale D. Ellis,et al.  A SHALLOW-WATER NORMAL-MODE REVERBERATION MODEL , 1995 .

[27]  C. Brennen,et al.  Acoustical Absorption and Scattering Cross Sections of Spherical Bubble Clouds , 1988 .

[28]  P. Bonmarin,et al.  Geometric properties of deep-water breaking waves , 1989, Journal of Fluid Mechanics.

[29]  C. T. Tindle,et al.  Complex effective depth of the ocean bottom , 1993 .