Frequency Analyzed Laser Light Scattering (Falls)

A simple and robust light scattering technique for spray diagnostics was developed. The technique provides a spray's intact length and breakup frequency. Scattered light is collected from a laser sheet that illuminates a portion of the spray. The scattered light is imaged on a fast photodiode whose output is sampled at 20 kHz. Fast Fourier transform (FFT) analysis is performed on the sampled signal. The shape of the FFT produced can be correlated to one of three distinct spray regimes: intact sheet, ligaments, or droplets. Strobe and laser illuminated photographs are also shown for reference.