Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-13T01:37:24.336Z Has data issue: false hasContentIssue false

Numerical calculation of the underwater noise of rain

Published online by Cambridge University Press:  26 April 2006

Hasan N. Oǧuz
Affiliation:
Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA
Andrea Prosperetti
Affiliation:
Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA

Abstract

When raindrops with a diameter of the order of 1 mm hit a plane water surface they entrain air bubbles that radiate noise in the course of volume oscillations. The paper presents a model of the underwater noise of rain produced by this process. The depth of submergence, radius, and initial energy of the entrained bubbles are obtained numerically for a number of drop sizes. The bubbles are assumed to radiate as dipoles, and the total underwater noise is calculated by integrating over the size of the entraining rain drops. The results are compared both with laboratory experiments of single-drop impacts and field data of rain noise. It is found that the model gives somewhat larger bubbles than are observed experimentally. As a consequence, the characteristic spectral peak of rain is predicted to occur at a somewhat lower frequency than found in experiment. However the level of the peak is in reasonable agreement with data. The amount of noise due to the process of drop impact itself is also estimated and found to be several orders of magnitude lower than the data. Therefore, in spite of some deficiencies of the model and of the computational results, the proposed mechanism for the underwater noise of rain is strongly supported by this study.

Type
Research Article
Copyright
© 1991 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Detsch, R. M. & Harris, I. A. 1990 Bubble entrainment by impacting drops in various liquid solutions. To be published.
Dingle, A. N. & Lee, Y. 1972 Terminal fallspeeds of raindrops. J. Appl. Met. 11, 877879.Google Scholar
Franz, G. J. 1959 Splashes as sources of sound in liquids. J. Acoust. Soc. Am. 31, 10801096.Google Scholar
Longuet-Higgins, M. S. 1990 An analytic model of sound production by rain-drops. J. Fluid Mech. 214, 395410.Google Scholar
Medwin, H. 1990 Impact and bubble radiation from obliquely incident rain. In Natural Physical Sources of Underwater Sound (ed. B. R. Kerman). Reidel, in press.
Medwin, H., Kurgan, A. & Nystuen, J. A. 1990 Impact and bubble sound from raindrops at normal and oblique incidence. J. Acoust. Soc. Am. 88, 413418.Google Scholar
Nystuen, J. A. 1986 Rainfall measurements using underwater ambient noise. J. Acoust. Soc. Am. 79, 972982.Google Scholar
Nystuen, J. A. 1990 An explanation of the sound generated by light rain in the presence of wind. In Natural Physical Sources of Underwater Sound (ed. B. R. Kerman). Reidel, in press.
Nystuen, J. A. & Farmer, D. M. 1989 Precipitation in the Canadian Atlantic Storms Program: Measurements of the acoustic signature. Atmos. Ocean 27, 237257.Google Scholar
Oguz, H. N. & Prosperetti, A. 1990a Bubble entrainment by the impact of drops on liquid surfaces. J. Fluid Mech. 219, 143179.Google Scholar
Oguz, H. N. & Prosperetti, A. 1990b Bubble oscillations in the vicinity of a nearly plane free surface. J. Acoust. Soc. Am. 87, 20852092.Google Scholar
Oguz, H. N. & Prosperetti, A. 1990c Bubble entrapment by axisymmetric capillary waves. In Engineering Science, Fluid Dynamics, A Symposium to Honor Theordore Yao-Tsu Wu (ed. G. T. Yates), pp. 191202. World Scientific.
Oguz, H. N. & Prosperetti, A. 1990d Drop impact and the underwater noise of rain. In Natural Physical Sources of Underwater Sound (ed. B. R. Kerman), Reidel, in press.
Prosperetti, A. 1984 Bubble phenomena in sound fields. Ultrasonics 22, 6977.Google Scholar
Prosperetti, A. 1991 The thermal behaviour of oscillating gas bubbles. J. Fluid Mech. 222, 587615.Google Scholar
Prosperetti, A., Pumphrey, H. C. & Crum, L. A. 1989 The underwater noise of rain. J. Geophys. Res. 94, 32553259.Google Scholar
Pumphrey, H. C. 1989 Sources of ambient noise in the ocean: an experimental investigation. PhD dissertation, University of Mississippi.
Pumphrey, H. C. & Crum, L. A. 1988 Acoustic emissions associated with drop impacts. In Natural Mechanisms of Surface-Generated Noise in the Ocean (ed. B. R. Kerman), pp. 463483. Reidel.
Pumphrey, H. C. & Crum, L. A. 1990 Free oscillations of near-surface bubbles as a source of the underwater noise of rain. J. Acoust. Soc. Am. 87, 142148.Google Scholar
Pumphrey, H. C., Crum, L. A. & Bjørnø, L. 1989 Underwater sound produced by individual drop impacts and rainfall. J. Acoust. Soc. Am. 85, 15181526.Google Scholar
Pumphrey, H. C. & Elmore, P. A. 1990 The entrainment of bubbles by drop impacts. J. Fluid Mech. 220, 539567.Google Scholar
Richardson, E. G. 1948 The impact of a solid on a liquid surface. Proc. Phys. Soc. 61, 352367.Google Scholar
Richardson, E. G. 1955 The sounds of impact of a solid on a liquid surface. Proc. Phys. Soc. 68, 541547.Google Scholar
Scrimger, J. A. 1985 Underwater noise caused by precipitation. Nature 318, 647649.Google Scholar
Scrimger, J. A., Evans, D. J., McBean, G. A., Farmer, D. M. & Kerman, B. R. 1987 Underwater noise due to rain, hail and snow. J. Acoust. Soc. Am. 81, 7986.Google Scholar
Scrimger, J. A., Evans, D. J. & Yee, W. 1989 Underwater noise due to rain — Open ocean measurements. J. Acoust. Soc. Am. 85, 726731.Google Scholar