Dispersion in Homogeneous Estuary Flow

TLDR: In this paper, the effects of transverse variations of velocity on dispersion in oscillatory, estuary flow are investigated and the dispersion coefficient (iE) is found to depend on a parameter (iT′ = \IT/T\dc\N), in which \iT is the tidal period and \IT\dc/N is a characteristic time for turbulent diffusion.

Abstract: The effects of the transverse variations of velocity on dispersion in oscillatory, estuary flow are investigated. The dispersion coefficient (\iE) is found to depend on a parameter \iT′ = \IT/T\dc\N, in which \iT is the tidal period and \IT\dc\N is a characteristic time for turbulent diffusion. Applying the relationship between \iE and \iT′ to some estuaries, it is concluded that the effects of the transverse variations of velocity may cause \iE to be as much as 10 times greater than it would be if only the vertical variations were considered. However, for continuous injection conditions, this possible increase in \iE appears to cause calculated concentrations to change by only 10% to 15% of the maximum concentration. Thus, under the conditions and assumptions stated in the paper, equations such as Elder’s or Taylor’s may be used to estimate \iE for continuous injections into estuaries. In other cases, it may be desirable to know the transverse distribution of velocity in order to estimate \iE.