THOUGHTS ON THE PROBLEM OF AERODYNAMIC NOISE SOURCES NEAR SOLID BOUNDARIES,

Abstract

The Report deals with a development of Curle's equations governing sound radiated by surface dipoles, which establishes, directly from those equations, the reflection phenomenon first noted by Powell. The development is for a particular situation, not easily treated by Powell's result, that of a turbulent boundary layer on a rigid flat plate radiating sound to a point so distant that the surface appears small. The development takes such a form that an estimate of the plate size, above which the dipole contribution vanishes and the plate assumes its role of an acoustic reflector, is made possible. The estimate, which is essentially an approximate one, suggests that surfaces have to be very large indeed before they become good reflectors. (Author)

Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1963
Accession Number
AD0436676

Entities

People

  • J. E. Ffowcs Williams

Organizations

  • AGARD

Tags

DTIC Thesaurus Topics

  • Aerodynamic Noise
  • Aerodynamics
  • Boundaries
  • Boundary Layer
  • Demographic Cohorts
  • Equations
  • Flow
  • Fluid Mechanics
  • Layers
  • Noise
  • Reflection
  • Reflectors
  • Specialists
  • Turbulent Boundary Layer
  • Turbulent Flow

Fields of Study

  • Physics

Readers

  • Acoustics.
  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Fluid Mechanics and Fluid Dynamics.