New Velocity Measuring Technique Using Dual-Scatter Laser Doppler Shift
Abstract
Conventional laser Doppler velocimeters (LDV) detect velocity by heterodyning scattered, Doppler shifted radiation with unscattered, reference radiation. A new dual-scatter LDV technique is described which simultaneously illuminates a moving scatterer from two different directions and heterodynes the two superimposed radiations simultaneously scattered in a common direction. Significant advantages are derived from the fact that the Doppler difference frequency thus obtained is independent of the scattered direction, permitting unusually large quantities of scattering radiation to be collected without adversely affecting the signal frequency dispersion; these advantages include enhanced signal-to-noise performance and a capability to measure fluid flows with unusually high velocity and/or low seed density. System performance, experimental verifications, and typical system designs are presented.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1970
- Accession Number
- AD0876458
Entities
People
- D. B. Brayton
- W. H. Goethert
Organizations
- Arnold Engineering Development Complex