The Generation of a Tollmien-Schlichting Wave by a Sound Wave,

Abstract

A spectral numerical method is used to study the two-dimensional unsteady flow over a flat plate in the presence of a plane sound wave propagating parallel to the flow. For s = omega x/u at infinity > 0(1), no observable interaction or energy interchange between the sound wave and the Tollmien-Schlichting wave is present. In the region s < or = 0(1), near the leading edge, an interaction occurs; the magnitude of this interaction is computed. A plane sound wave with dimensionless frequency omega nu/U-square at infinity = .000056 generates a Tollmien-Schlichting wave of the same frequency and an amplitude at the first neutral point .0001 times the sound-wave amplitude. Computations at a second, lower frequency result in a lower neutral point amplitude. The response of the boundary layer to large unsteady disturbances is discussed and compared with published behavior based on the boundary layer equations. Solutions of the Orr-Sommerfeld equation are examined and found to have a different character for s > or < 0(1) consistent with the more complete equations. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Aug 31, 1979
Accession Number
ADA075816

Entities

People

  • John W. Murdock

Organizations

  • The Aerospace Corporation

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Acoustic Propagation
  • Acoustic Waves
  • Amplitude
  • Boundaries
  • Boundary Layer
  • Continuous Waves
  • Equations
  • Flow
  • Frequency
  • Layers
  • Leading Edges
  • Reynolds Number
  • Sound Waves
  • Two Dimensional
  • Unsteady Flow
  • Waves

Fields of Study

  • Physics

Readers

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