Prediction of High-Speed Rotor Noise with a Kirchhoff Formula,

Abstract

A new method has been developed to predict the impulsive noise generated by a transonic rotor blade. The formulation uses a full-potential finite-difference method to obtain the pressure field close to the blade. A Kirchhoff integral formulation is then used to extend these finite difference results into the far-field. This Kirchhoff formula, written in a blade-fixed coordinate system, requires initial data across a plane at the sonic radius. This data is provided by the finite-difference solution. Acoustic pressure predictions show excellent agreement with hover experimental data for two hover cases of 0.88 and 0.90 tip Mach number, the latter of which has delocalized transonic flow. These results represent the first successful prediction technique for peak pressure amplitudes using a computational code.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1987
Accession Number
ADA178982

Entities

People

  • Roger C. Strawn
  • Timothy W. Purcell
  • Yung H. Yu

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Acoustics
  • Amplitude
  • Blade Tips
  • Computational Fluid Dynamics
  • Computations
  • Equations
  • Experimental Data
  • Far Field
  • Fluid Dynamics
  • Fluid Flow
  • Geometry
  • Helicopter Rotors
  • Mach Number
  • Models
  • Pressure Distribution
  • Transonic Flow
  • Turbulent Mixing

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Calculus or Mathematical Analysis