Distributed laser Doppler velocimeter

Abstract

A monobeam laser Doppler velocimeter that permits continuous recovery of the flow velocity profile along the beam is described. The scheme applies the coherence-multiplexing concept to backscattering Doppler detection. A theoretical analysis of the distributed velocimeter is given, along with a description of an experiment with a superluminescent diode source inserted in an all-fiber-optic scheme. The velocity profile of water flow in a duct is reported. The results confirm the exceptional capabilities offered by this velocimeter in experimental fluid mechanics.