Experimental Studies of Relative Diffusion in Lake Huron

Abstract

Experimental data were obtained in Lake Huron on the distribution of mean concentration and meansquare fluctuation about the center of gravity of a diffusing plume of fluorescent dye. Some of the mean concentration profiles showed a skewness attributable to the vertical current shear, while others were approximately Gaussian. The ratio of rms concentration fluctuation to local mean appears to be a quasi-universal distribution, in the sense that the typical amplitude of this ratio depends on turbulence intensity, but otherwise individual distributions are similar, their length-scale being equal to the length-scale of the mean concentration distribution.