Relative Diffusion in Nonisotropic Turbulence

Based on knowledge of those turbulent water-flow conditions, which establish the minimum rate of turbulent surface diffusion, a simple relation is derived for the estimation of the rate of minimum dilution in nonisotropic bottom-generated surface turbulence, when the dimensions of the diffusion phenomenon is of the order of magnitude of the depth of water, and the movements of the fluid particles are mutually correlated. Two series of relative two-particle surface diffusion in laboratory flumes combined with measurements of space correlation coefficients show that the friction coefficient, depth, and downstream distance are the only parameters needed for a reliable prediction of the frequency distribution of the surface pollution of a conservative substance.