Effect of Bed and Side Roughness on Dispersion in Open Channels

Abstract

Dispersion in open‐channel flow is significantly affected by boundary roughness. The analysis of data generated in the present experimental program shows that the dimensionless dispersion coefficient is a function of two interacting mechanisms, namely, resistance and blockage effect due to roughness elements. The dispersion characteristics of channels with rough beds are found to be analogous to those of channels with rough sides. The proposed parameter P, which incorporates the influence of resistance and blockage effect, yields a good correlation with the available dispersion data. The empirical model developed in the present study may be used to predict dispersion coefficients in straight laboratory and field channels.