Simultaneous measurement of diameter and position of spherical particles in a spray by an original imaging method

The size and the position of individual particles in a falling spray crossing a horizontal plane are measured simultaneously with a shadowgraph imaging setup. An original method for measurement of drop sizes based on a prescribed analytical form of the luminance distribution of the objects (i.e., the drops) is presented. The processing time is strongly reduced compared with that for the usual inversion techniques. The turbulent dispersion of drops in a grid-generated turbulence is studied. Evidence for the presence of coalescence in the spray is presented.