Attenuation of Cavity Bay Noise

Abstract

This report concludes the investigation into the attenuation of cavity bay noise conducted under EOARD Award number FA8655-11-1-3025. A preliminary report was provided to EOARD in April 2012 and can be considered in conjunction with this final report. This investigation covers the experimental analysis and the development of passive palliative devices at both 1/40th and 1/20th scale and under both subsonic and supersonic conditions. Two methods of attenuation are of interest. The first is a resonant array based on the principle similar to that of a Helmholtz resonator and the second is a device comprised of a porous wire mesh coupled with a confined backing volume. The resonant arrays provide a source of viscous losses which can be targeted at the frequencies of the Rossiter modes within the cavity and the porous mesh devices provide viscous losses over a broader range of frequencies.

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Document Details

Document Type
Technical Report
Publication Date
Oct 01, 2012
Accession Number
ADA571107

Entities

People

  • David G. Macmanus

Organizations

  • Cranfield University

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies
  • Materials and Manufacturing Processes
  • Weapons Technologies

DTIC Thesaurus Topics

  • Absorption Coefficients
  • Acoustic Properties
  • Air Force
  • Air Force Facilities
  • Air Force Research Laboratories
  • Aircrafts
  • Attenuation
  • Boundary Layer
  • Frequency
  • Mach Number
  • Resonant Frequency
  • Resonators
  • Reynolds Number
  • Standing Waves
  • Turbulent Mixing
  • Wind Tunnel Tests
  • Wind Tunnels

Fields of Study

  • Physics

Readers

  • Acoustical Oceanography.
  • Computational Fluid Dynamics (CFD)
  • Electronics Engineering

Technology Areas

  • Hypersonics