Model for Vertical Diffusion in Stratified Flows
Publication: Journal of Hydraulic Engineering
Volume 112, Issue 11
Abstract
A model is presented for the calculation of vertical diffusion in stratified flows dominated by bottom shear. The model includes a very simplified representation of the potential energy (rotation against buoyancy forces) and kinetic energy of turbulent eddies. The two universal model constants are derived from measurements of vertical mixing in open‐channel flow. Analytical expressions are given for the vertical diffusion coefficient in the special cases of two‐layer flows and linearly stratified flows. Numerical calculations are necessary to obtain for arbitrarily stratified flows. Application of the method using a numerical one‐dimensional diffusion model shows good agreement between the calculated density profiles and profiles measured in laboratory and field situations. A practical application is the prediction of the stratification evolution near a cooling water or wastewater disposal point in a receiving flow. The model needs the input of the vertically averaged flow velocity and an initial density profile.
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Published In
Journal of Hydraulic Engineering
Volume 112 • Issue 11 • February 1986
Pages: 1069 - 1086
Copyright
Copyright © 1986 ASCE.
History
Published online: Feb 1, 1986
Published in print: Feb 1986
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