FEASIBILITY OF A DIRECT EXPERIMENTAL TEST OF LIGHTHILL'S THEORY OF AERODYNAMIC SOUND USING FOCUSING TECHNIQUES,

Abstract

A direct experimental test of Lighthill's theory of aerodynamically generated sound is found to be feasible if a suitable focusing device is used. By sampling the sound from a single correlation volume only, major theoretical problems could be overcome. Calculations were made for the case of sound produced in a single correlation volume in the downstream portion of an experimentally realizable subsonic jet. These show that the power level and frequency spectrum of the acoustic signal should be of such a nature that they could be adequately handled by the apparatus described. (Author)

Document Details

Document Type
Technical Report
Publication Date
Jul 18, 1957
Accession Number
AD0657159

Entities

People

  • S. A. Elder

Organizations

  • Johns Hopkins University Applied Physics Laboratory

Tags

DTIC Thesaurus Topics

  • Acoustic Signals
  • Collecting Methods
  • Frequency
  • Power Levels
  • Sampling
  • Spectra
  • Wave Phenomena

Fields of Study

  • Physics

Readers

  • Acoustics.
  • Aerodynamics.
  • Electronics Engineering