Internal Wave Measurement
Final rept. 12 Apr-31 Oct 1977
SPECTRON DEVELOPMENT LABS INC COSTA MESA CA
Pagination or Media Count:
A laser velocimeter LV is a system which measures the velocity of a fluid by detecting the frequency of sinusoidal variations of laser light scattered by particles suspended in and moving with the fluid. Two types of remote backscatter systems have been developed for laboratory applications. The fringe or dual beam type LV system produces a sinusoidal interference pattern at the intersection of two crossed, focussed, coherent laser beams. A transverse velocity component is measured by the frequency of the particle crossing the projected fringes. A reference beam or optical heterodyne system is also possible in which the Doppler shift due to the axial velocity component of the scatterers is measured. At a workshop on laser Doppler velocimetry ARPA expressed interest in using laser velocimetry systems for the measurement of internal waves and other small ocean velocity fluctuations. The conclusion of the meeting was that such measurements were probably achievable to the desired accuracy using a fringe LV system, but feasibility should be established by design experiment and analysis. This report describes the results of a study.
- Physical and Dynamic Oceanography
- Test Facilities, Equipment and Methods