A New Method for Directional LDA-Velocity Measurement of Lateral and Axial Components Using Diffraction Gratings,

Abstract

Using diffraction gratings as beam splitters in LDA systems the resulting fringe spacing becomes achromatic. Thus employing unstabilized laser diodes of different wavelengths, distinguishable fringe systems with identical fringe spacings int he measuring volume can be generated. The evaluation of at least two LDA burst signals and their signal phase corresponding to the different fringe systems locally parallel shifted and/or tilted against each other allows the directional measurement of lateral and axial velocity components without using frequency shift techniques. Based upon the new techniques inexpensive and compact multicomponent LDA sensors for the directional measurement of lateral and axial velocity components can be realized. (Author)

Document Details

Document Type
Technical Report
Publication Date
Jul 23, 1992
Accession Number
ADP008906

Entities

People

  • D. Dopheide
  • H. Mueller

Organizations

  • Technical University of Lisbon

Tags

DTIC Thesaurus Topics

  • Achromatic
  • Computers
  • Diffraction
  • Directional
  • Fluid Mechanics
  • Frequency
  • Frequency Shift
  • Gratings (Spectra)
  • Laser Diodes
  • Lasers
  • Measurement
  • Mechanics
  • Portugal
  • Test And Evaluation

Fields of Study

  • Physics

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Fluid Dynamics.
  • Image Processing and Computer Vision.

Technology Areas

  • Directed Energy
  • Space
  • Space - Hall-Effect Thruster