Deriving Longitudinal Dispersion Coefficient Based on Shiono and Knight Model in Open Channel

Abstract

In this study, a theoretical formula for a one-dimensional longitudinal dispersion coefficient was developed using the lateral distribution equation for depth-averaged streamwise velocity derived from the Shiono and Knight model. A set of experimental results that included detailed velocity and tracer concentration data acquired from natural rivers was used to verify the developed dispersion formula. Additionally, the developed formula was compared with existing empirical equations for the longitudinal dispersion coefficient. From this comparison, it could be seen that the results of this study showed a close approximation to the observed dispersion coefficient, although the agreement was not best. The developed equation could be used in cases where the dispersion coefficient must be determined based only on topographic or hydraulic information rather than detailed flow data.