Accession Number : AD0866034

Title :   Laser Doppler Measurement of Water Velocity.

Descriptive Note : Research and development rept.,

Corporate Author : NAVAL SHIP RESEARCH AND DEVELOPMENT LAB ANNAPOLIS MD

Personal Author(s) : Rockett, Paul D. ; Laster, D. R. ; Decker, W. A.

Report Date : MAR 1970

Pagination or Media Count : 40

Abstract : The feasibility of measuring ship's speed by the doppler shift in light scattered from a laser beam is investigated. Theoretical aspects of the Doppler effect and optical processing are discussed. The significant design parameters are enumerated and the effects of each analyzed. Problems encountered while testing a bread-board model of a laser water speed sensor reveal certain design criteria and aid in a model design review. It is concluded that with lasers available today the laser log concept is feasible, but difficult and expensive to implement. Optical heterodyning of the source and scattered laser beams results in a signal, readily amenable to electronic processing, but often hidden in noise. It is also concluded that the characteristics of a laser doppler speed-sensing system make it far more valuable as a laboratory tool for studying small-scale flow phenomena and turbulence. (Author)

Descriptors :   (*FLOWMETERS, PERFORMANCE(ENGINEERING)), (*LASERS, DOPPLER EFFECT), DOPPLER SYSTEMS, COHERENT SCATTERING, LAMINAR FLOW, TURBULENCE, COHERENT RADIATION, SCATTERING, WATER, VELOCITY, MEASURING INSTRUMENTS, MODEL TESTS, CALIBRATION.

Subject Categories : Lasers and Masers
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE