Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-28T22:15:23.001Z Has data issue: false hasContentIssue false
  • English
  • Français

A theoretical study on drop impact sound and rain noise

Published online by Cambridge University Press:  26 April 2006

Y. P. Guo  and
J. E. Ffowcs Williams
Y. P. Guo
Affiliation:
Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK Present address: Department of Ocean Engineering, MIT, Cambridge, MA 02139, USA.
J. E. Ffowcs Williams
Affiliation:
Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK
Get access Rights & Permissions [Opens in a new window]

Abstract

This paper examines the sound waves generated when a spherical water drop impacts upon an initially quiescent water surface. The pressure fluctuations and the acoustic energy radiated by the initial impact are calculated analytically. It is shown that the rapid momentum exchange between the fluid in the falling drop and that in the main water body causes the radiation of compressive waves. These waves are radiated in the form of a wave packet with a densely packed edge which is heard in the far field as a noisy shock-like pulse followed by a quickly decreasing tail. The wave packet carries with it sound energy proportional to the kinetic energy of the falling drop and to the cube of the impact Mach number. Applications of these analytic results to the study of noise from natural rain are discussed, and an illustrative example is given where the noise level due to rain showers is linearly related to the rainfall rate, which is shown to be consistent with observations.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 227 , June 1991 , pp. 345 - 355
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

Dowling, A. P. & Ffowcs Williams, J. E. 1983 Sound and Sources of Sound. Ellis Horwood.
Franz, G. J. 1959 Splashes as sources of sound in liquids. J. Acoust. Soc. Am. 31, 1080–1096.Google Scholar
Gradshteyn, I. S. & Ryzhik, I. M. 1980 Tables of Integrals, Series, and Products. Academic.
Guo, Y. P. 1986 Wave-induced sound in the ocean. Ph.D. thesis, University of Cambridge.
Jones, D. S. 1982 The Theory of Generalized Functions. Cambridge University Press.
Lighthill, M. J. 1952 On sound generated aerodynamically: I. General theory.. Proc. R. Soc. Lond. A 211, 564–587.Google Scholar
Minnaert, M. 1933 On musical air-bubbles and the sounds of running water. Phil. Mag. 16, 235–248.Google Scholar
Nystuen, J. A. 1986 Rainfall measurements using underwater ambient noise. J. Acoust. Soc. Am. 79, 972–982.Google Scholar
Ogtuz, H. N. & Prosperetti, A. 1990 Bubble entrainment by the impact of drops on liquid surfaces. J. Fluid Mech. 219, 143–179.Google Scholar
Plesset, M. S. & Prosperetti, A. 1977 Bubble dynamics and cavitation. Ann. Rev. Fluid Mech. 9, 145–185.Google Scholar
Prosperetti, A., Crum, L. A. & Pumphrey, H. C. 1989 The underwater noise of rain. J. Geophys. Res. 94, 3255–3259.Google Scholar
Pumphrey, H. C., Crum, L. A. & Bjorno, L. 1989 Underwater sound produced by individual drop impacts and rainfall. J. Acoust. Soc. Am. 85, 1518–1526.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, 79–86.Google Scholar
Strasberg, M. 1956 Gas bubbles as sources of sound in liquids. J. Acoust. Soc. Am. 28, 20–26.Google Scholar
Wenz, G. W. 1962 Acoustic ambient noise in the ocean: spectra and sources. J. Acoust. Soc. Am. 34, 1936–1956.Google Scholar