Article ID Journal Published Year Pages File Type
5770892 Journal of Hydrology 2017 11 Pages PDF
Abstract

•To illustrate the dispersion process in a reversal laminar flow.•To analytically derive the vertical concentration distribution functions.•To characterize the two-dimensional concentration evolution in Taylor dispersion stage.

Pollutant transport in reversal laminar flows gains its significance in various coastal regions. Since oscillation in the flow introduces much complexity into the transport process, little progress has been made to illustrate the evolution of concentration distribution. In this work, the first order expansion of the generalized dispersion model, as a simplified applicable method based on the previously proposed Aris-Gill expansion (Wang and Chen, 2016b,c), is applied to analytically study the pollutant dispersion in an open channel reversal laminar flow. This method is conveniently used to accurately predict the two-dimensional concentration evolution characteristic of peak concentration position and duration. The vertical concentration difference is determined to be tremendous and vary periodically, and the peak concentration appears at the freesurface or bottom depending on the reversal amplitude. The approach for vertical concentration to uniformity in the dispersion process lasts longer remarkably in reversal flows than that in steady flows.

Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Earth-Surface Processes
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