Method and device for measuring velocity components with the aid of the relative laser Doppler anemometry

摘要

This method and device exhibit part-beams generated by optical beam division from a laser beam, which are radiated onto the optically scattering object. During this process, the information of the Doppler frequency change is taken from the scattered light of the scattered light fields associated with the part-beams, which in each case has different light frequencies in consequence of the Doppler effect, in the form of beat frequencies of the scattered light field resulting from interferometric heterodyning, by means of opto-electronic receivers, the received beat frequencies corresponding to the amounts of the velocity components which are in each case aligned perpendicularly to the angle-bisecting line of two part-beams. In order to be able to measure two mutually perpendicular velocity components at the same time, either at least one of the part-beams, after passing the scattering object, is radiated into itself or again onto the scattering object by coaxially opposite optical feedback to one of the other part-beams. Another possibility consists in forming and optically coaxially and oppositely feeding back another part-beam from additional beam division from the original laser beam. In both cases ... Original abstract incomplete. IMAGE