Experimental Studies of Impulsive Noise Produced by Spheres Moving through Water.

Abstract

It is known from previous experiments that freely falling spheres produce sudden noise bursts. The source of this noise is unknown and little is known about the conditions under which it occurs. In an attempt to study this phenomenon under controlled conditions, spheres were towed in an anechoic tank, Velocities up to 5 m/sec and Reynolds numbers up to 500,000 were obtained with spheres of 2, 4 and 10 inches diameter. After eliminating all mechanical and acoustical disturbances, no noise bursts could be detected. However, the impulsive noise was still observed in free-fall experiments, and a ranging system allowed the location of these noise bursts with respect to a fixed point. A frequency analysis was done with a digital signal processor.

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1980
Accession Number
ADA084419

Entities

People

  • Thomas Kunze

Organizations

  • Naval Postgraduate School

Tags

DTIC Thesaurus Topics

  • Amplifiers
  • Background Noise
  • Boundary Layer
  • Diameters
  • Electric Motors
  • Engineering
  • Flow
  • Foam Rubber
  • Frequency
  • Frequency Response
  • Noise
  • Physics
  • Power Amplifiers
  • Range Finding
  • Recording Systems
  • Reynolds Number
  • Tape Recorders

Readers

  • Acoustics.
  • Explosive Engineering.
  • Fluid Dynamics.