Statistical Analysis and Computer Simulation of Laser Doppler Velocimeter Systems

In a laser Doppler velocimeter the signal arises from the superposition of several pulses at random phase, and the instantaneous frequency recorded at the output, which is a measure of the velocity, contains an ambiguity component due to this effect. A statistical analysis is presented that predicts the ambiguity for both the mask and the Gaussian beam velocimeters and the results are shown to be in close agreement with experiment. Based on this theory, a computer simulation model has been developed that is a useful tool for analyzing and optimizing the parameters in a particular system. Finally, the specific applications of turbulence measurement in fluid flow is considered in more detail.