Correcting Spectral Density of Laser Doppler Anemometer Signals during Measuring of High-Speed Aerodynamic Flows. Part 1

Abstract

The first part of the work sets out the problem for a method of constructing correction coefficients to compensate for distortions introduced by the non-uniform frequency characteristics of the electronic path of a laser Doppler velocimeter into the spectral density of Doppler signals. The method relies on averaging a statistical ensemble of the spectral densities of noise signals obtained during illumination of a photodetector by a white light source, constructing the inverse function to the averaged spectral density acquired with truncation in the low- and high- frequency bands, and applying digital low-pass filtering to it. A model numerical experiment has been carried out. The results of the experiment are presented, and they confirm increase in the velocity measurement error as the flow rate grows.