Measurements of the attenuation of sound by a warm air fog

Abstract

Measurements of sound attenuation are presented for dimensionless frequencies near unity where the effects of mass transfer are dominant. The tests are made in a Wilson cloud chamber by measuring the rate of decay of the fundamental mode of acoustic oscillation which is excited during the operation of the chamber. Measurements of pressure and volume are made continuously during the expansion. Droplet size and concentration of the monodisperse fog are determined from time- resolved measurements of the optical transmission at two wavelengths of light.