A Note on the General Scaling of Helicopter Blade-Vortex Interaction Noise

Abstract

A model-rotor acoustic experiment in a three meter open section anechoic wind tunnel (CEPRA-19) is described. The important scaling parameters are reviewed and some on-line acoustic data are presented for conditions known to produce blade-vortex interaction noise on a single rotor helicopter. Time averages of the model-scale acoustic pulses are compared with similar full-scale data taken in-flight under the same non-dimensionalized conditions. Good general agreement between model and full-scale pulse shapes and amplitudes of blade- vortex interaction noise is shown for one advance ratio over a range of inflow conditions for the rotor. Directivity sweeps for a condition known to generate blade-vortex interactions are presented. Some model rotor testing limitations of the CEPRA-19 facility in its present configuration are indicated.

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Document Details

Document Type
Technical Report
Publication Date
May 01, 1982
Accession Number
ADA118761

Entities

People

  • C. Dahan
  • D. A. Boxwell
  • F. H. Schmitz
  • S. Lewy

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Acoustics
  • Aircrafts
  • Airfoils
  • Airframes
  • Amplitude
  • Construction
  • Flight
  • Frequency
  • Helicopter Rotors
  • Helicopters
  • Mach Number
  • Measurement
  • Reflection
  • Shape
  • Turbulent Mixing
  • United States
  • Wind Tunnels

Fields of Study

  • Physics

Readers

  • Acoustics.
  • Aerospace Engineering
  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.