The Effect of Uniform Flow on the Dynamics and Acoustics of Force-Excited Infinite Plates.

Abstract

Formulae are obtained for the time-harmonic steady-state plate displacement, acoustic pressure and particle velocities. The far-field pressure is obtained fro a stationary phase approximation, and two separate formulations are used to define a time-averaged acoustic intensity vector. The stability of a line-excited plate is examined using both a steady-state approach and a causal approach which is able to distinguish between absolute and convective instability. Some numerical results are presented for a steel plate vibrating in water. The far-field pressure is not significantly affected by flow speeds of a practical magnitude. The very low-frequency acoustic intensity vectors at the plate surface are affected considerably, but at higher frequencies there is no significant effect. At low flow speeds a convective instability is found and at higher flow speeds there is an absolute instability. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1982
Accession Number
ADA124576

Entities

People

  • D. J. Atkins

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Acoustic Velocity
  • Acoustic Waves
  • Acoustics
  • Boundary Layer
  • Dispersion Relations
  • Equations
  • Far Field
  • Fluid Flow
  • Frequency
  • Geometry
  • Group Velocity
  • Mach Number
  • Molecular Dynamics
  • Sound Pressure
  • Steady State
  • Very Low Frequency
  • Wave Propagation

Fields of Study

  • Physics

Readers

  • Electromagnetic Wave Scattering and Antenna Radiation Engineering
  • Fluid Dynamics.