Perforated Wall Noise in the AEDC-PWT 16-ft and 4-ft Transonic Tunnels

Abstract

The report presents the results of recent studies of noise in Propulsion Wind Tunnel (16T) and Aerodynamic Wind Tunnel (4T). Noise levels in the free stream and at the test section wall were measured in both tunnels as a function of Mach number, Reynolds number, wall angle, and wall porosity. In Tunnel 4T, free-stream noise characteristics were also evaluated with solid (taped) test section walls. Test results revealed that the perforated test section wall holes generate discrete frequency, high energy noise. In Tunnel 16T, there is a critical Mach number range in which a wall hole frequency. Test section noise levels were found to vary slightly with wall angle and significantly with Mach number and wall porosity. The wall porosity corresponding to the minimum noise levels was found in Tunnel 4T.

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Document Details

Document Type
Technical Report
Publication Date
Oct 01, 1971
Accession Number
AD0888561

Entities

People

  • O. P. Credle

Organizations

  • Arnold Engineering Development Complex

Tags

Communities of Interest

  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Acoustic Insulation
  • Air Force
  • Boundaries
  • Boundary Layer
  • Compressor Blades
  • Flow
  • Flow Visualization
  • Free Stream
  • Frequency
  • Governments
  • Layers
  • Mach Number
  • Measurement
  • Pressure Measurement
  • Reynolds Number
  • Test And Evaluation
  • Wind Tunnels

Fields of Study

  • Physics

Readers

  • Fluid Dynamics.
  • Speech Processing/Speech Recognition.