The Effect of Monomolecular Films on Low Sea State Ambient Noise

Abstract

A series of experiments conducted during low sea state conditions show that surface-related ambient noise is significantly reduced beneath monomolecular films. Although the amount of noise reduction varies between experiments, the highest attenuations reach 8 dB for frequencies of 1 kHz and higher. The ambient noise spectra beneath these films generally resemble those of non-filmed lower sea states. Preliminary low sea state experiments, providing simultaneous aural and visual monitoring of the sea surface from a depth of one meter, suggest that, in the absence of whitecapping, films attenuate surface noise by dramatically reducing the number of microbreaks which are associated with bubble entraining noise.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1991
Accession Number
ADA240224

Entities

People

  • Garr Updegraff
  • Jim J. Rohr

Tags

Communities of Interest

  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Ambient Noise
  • Background Noise
  • Bubbles
  • Capillary Waves
  • Detectors
  • Films
  • Frequency
  • Materials
  • Measurement
  • Monomolecular Films
  • Noise
  • Noise Reduction
  • Sound Pressure
  • Spectra
  • Surface Active Substances
  • Video
  • Video Cameras

Fields of Study

  • Environmental science

Readers

  • Acoustics.
  • Coastal Oceanography
  • Thin Film Deposition Science.