Abstract
To estimate the turbulent diffusion coefficient and the particle fall velocity for suspended kaolin in open channel flow, distributions of concentration were measured using image processing. This measurement is the way that a two-dimensional vertical distribution of concentration is indirectly acquired by processing the picture recorded by a commercial video. Vertical profiles of turbulent diffusion coefficient and particle fall velocity were assessed from concentration distributions obtained by the method and advection diffusion equation, and then examined on relation to turbulent characteristics of flow. As estimating two hydraulic parameters, a fuzzy linear regression model was utilized to remove local errors in the measured concentration distributions. It was seem that the fall velocity was lowered as increasing in turbulent intensity or Reynolds stress and was notably associated with the power spectrum in rather higher frequency than lower one. It was shown that the turbulent diffusion coefficient was influenced by the energy spectrum in lower wave numbers.
