Dispersion of Floating Particles in Uniform Channel Flow

An investigation is given of the dispersion of small particles floating on the surface of an open channel with uniform flow and wide rectangular cross section. The dispersion was exclusively due to the diffusion caused by surface turbulence. The surface turbulence is two-dimensional, homogeneous and nondecaying. The dispersion experiments were supplemented by measurements of the turbulence intensities and correlation functions just below the surface of the water. The turbulence was found to be anisotropic, the longitudinal dispersion being nearly twice the lateral dispersion. By the application of an established relation between the Lagrangian and Eulerian correlation functions and a principle of Reynolds' number similarity, a simple description of the one-particle diffusion is obtained.