Significance of buoyancy in turbulence closure for computational fluid dynamics modelling of ultraviolet disinfection in maturation ponds

Dahl, N.W., Woodfield, P.L., Simpson, B.A.F. ORCID: 0000-0002-4615-5708, Lemckert, C.J. and Stratton, H.M., 2018. Significance of buoyancy in turbulence closure for computational fluid dynamics modelling of ultraviolet disinfection in maturation ponds. Water Science and Technology. ISSN 0273-1223

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Abstract

Buoyancy-driven turbulent dispersion in a maturation pond is studied by a combination of field measurements and computational fluid dynamics. Modelling flow in maturation ponds requires turbulent closure models because of the large physical size and the need to model on diurnal time scales. Simulation results are shown to be more sensitive to the inclusion of a buoyancy production term appearing in the turbulent transport equations than to the model choice. Comparisons with experimental thermal profiles show that without this term, thermal mixing is over predicted. When including the term, stratification occurs but thermal mixing is under-predicted in the lower water column. In terms of pond performance, the effect of this term is to cause increased surface die-off of Escherichia coli during sunlight hours due to the generation of stratification. It is recommended that future modelling consider and implement this term.

Item Type: Journal article
Alternative Title: Role of buoyancy for ultraviolet disinfection in maturation ponds
Publication Title: Water Science and Technology
Creators: Dahl, N.W., Woodfield, P.L., Simpson, B.A.F., Lemckert, C.J. and Stratton, H.M.
Publisher: IWA Publishing
Date: 12 January 2018
ISSN: 0273-1223
Identifiers:
NumberType
10.2166/wst.2018.012DOI
Divisions: Schools > School of Science and Technology
Depositing User: Linda Sullivan
Date Added: 21 Feb 2018 12:23
Last Modified: 21 Feb 2018 12:23
URI: http://irep.ntu.ac.uk/id/eprint/32778

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