Rotor Broadband Noise Resulting from Tip Vortex/Blade Interaction.

Abstract

The study described was conducted to investigate tip vortex/blade interaction as a source of broadband noise to hovering helicopter rotors. Observations of full scale, multi-blade rotors indicate that at moderate to high lift conditions the tip vortex, passing beneath a blade caused a stall pocket to form near the blade tip. At these same lift conditions rotor noise (expressed as Perceived Noise Level) was observed to increase at a faster rate than for lower lift conditions. This behavior has been termed 'noise divergence.' An experimental investigation was conducted in the UARL Acoustic Research Wind Tunnel to define the noise characteristics associated with this tip vortex/blade interaction.

Document Details

Document Type
Technical Report
Publication Date
Feb 01, 1975
Accession Number
ADA020692

Entities

People

  • Charles L. Munch
  • Henry Day
  • Robert W. Patterson

Organizations

  • United Technologies Corporation

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aircrafts
  • Airframes
  • Blade Tips
  • Blades
  • Broadband
  • Helicopter Rotors
  • Helicopters
  • High Lift
  • Hovering
  • Observation
  • Wind Tunnels

Fields of Study

  • Physics

Readers

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