Simultaneous measurement of particle size and velocity via the scattered light intensity of a real fringe laser anemometer

The scattered light from spherical particles irradiated by a real fringe laser anemometer was calculated. The scattering theory of Mie was applied to each beam separately and the resulting fields added. The intensity was then numerically integrated over a finite receiving aperture. The analysis shows that by varying the incident angle of the beams and the size of the receiving aperture, the system can be optimized so that particles from submicron to approximately 30 microns can be sized by measuring the scattered light intensity. Thus, together with the Doppler frequency, the size and velocities can be obtained. Both forward and backscattering modes were examined.