TRANSVERSE MIXING IN NATURAL OPEN CHANNELS

摘要

Contamination of natural watercourses is an area of growing international concern. Understanding the processes of transverse mixing is fundamental to describing the fate and impact of contaminants in open channel flows. These processes are poorly understood for natural channels, particularly in the presence of planform curvature. Comparison of a technique for evaluating transverse mixing coefficients in the presence of planform curvature from bulk channel properties, presented by Boxall and Guymer (2003), is compared with the data set of Krishnappen and Lau (1977 a & b). The Boxall and Guymer (2003) method evaluates the dispersion (shear) effects of major secondary circulation currents predicted from planform curvature effects, in conjunction with an assumed inter-zone mixing rate. This method is found to recreate the magnitude and variation in coefficients determined from the original data.