Spectral Analysis of the Signal from the Laser Doppler Velocimeter. Turbulent Flows,

Abstract

The power spectrum of phototube current from a Laser Doppler Velocimeter operating in the heterodyne mode has been computed. The spectrum is obtained in terms of the space time correlation function, for turbulent flow of the fluid. The spectral width and shape predicted by the theory is in agreement with experiment. For normal operating parameters the time average spectrum contains information only for times shorter than the Lagrangian integral time scale of the turbulence. To examine the long time behavior one must use either extremely small scattering angles much longer wavelength radiation or a different mode of signal analysis, e.g., F.M. detection. (Author)

Document Details

Document Type
Technical Report
Publication Date
Mar 28, 1972
Accession Number
AD0743530

Entities

People

  • John C. Angus
  • John W. Dunning Jr
  • Robert V. Edwards

Organizations

  • Case Western Reserve University

Tags

DTIC Thesaurus Topics

  • Agreements
  • Detection
  • Diffraction
  • Flow
  • Integrals
  • Phototubes
  • Power Spectra
  • Radiation
  • Scattering
  • Spectra
  • Turbulence
  • Turbulent Flow
  • Velocimeters

Fields of Study

  • Physics

Readers

  • Approximation Theory.
  • Fluid Dynamics.
  • Optical Physics and Photonics.

Technology Areas

  • Directed Energy
  • Space