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

N. W. Dahl, P. L. Woodfield, B. A.F. Simpson, C. J. Lemckert, H. M. Stratton

Research output: Contribution to journalArticle

Abstract

Buoyancy-driven turbulent dispersion in a maturation pond is studied using 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 timescales. 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.

Original languageEnglish
Pages (from-to)1372-1385
Number of pages14
JournalWater Science and Technology
Volume77
Issue number5
DOIs
Publication statusPublished - 1 Mar 2018

Fingerprint

Disinfection
Ponds
computational fluid dynamics
Buoyancy
disinfection
buoyancy
maturation
Computational fluid dynamics
Turbulence
pond
turbulence
stratification
modeling
flow modeling
Escherichia coli
water column
timescale
simulation
Hot Temperature
Water

Cite this

@article{6b59bc8ac9fb46d4ae2ce58293747870,
title = "Significance of buoyancy in turbulence closure for computational fluid dynamics modelling of ultraviolet disinfection in maturation ponds",
abstract = "Buoyancy-driven turbulent dispersion in a maturation pond is studied using 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 timescales. 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.",
keywords = "Buoyancy production term, E. coli, Inactivation, Kinetic modeling",
author = "Dahl, {N. W.} and Woodfield, {P. L.} and Simpson, {B. A.F.} and Lemckert, {C. J.} and Stratton, {H. M.}",
year = "2018",
month = "3",
day = "1",
doi = "10.2166/wst.2018.012",
language = "English",
volume = "77",
pages = "1372--1385",
journal = "Progress in Water Technology",
issn = "0273-1223",
publisher = "Iwa Publishing",
number = "5",

}

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.; Lemckert, C. J.; Stratton, H. M.

In: Water Science and Technology, Vol. 77, No. 5, 01.03.2018, p. 1372-1385.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Significance of buoyancy in turbulence closure for computational fluid dynamics modelling of ultraviolet disinfection in maturation ponds

AU - Dahl, N. W.

AU - Woodfield, P. L.

AU - Simpson, B. A.F.

AU - Lemckert, C. J.

AU - Stratton, H. M.

PY - 2018/3/1

Y1 - 2018/3/1

N2 - Buoyancy-driven turbulent dispersion in a maturation pond is studied using 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 timescales. 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.

AB - Buoyancy-driven turbulent dispersion in a maturation pond is studied using 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 timescales. 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.

KW - Buoyancy production term

KW - E. coli

KW - Inactivation

KW - Kinetic modeling

UR - http://www.scopus.com/inward/record.url?scp=85044279754&partnerID=8YFLogxK

U2 - 10.2166/wst.2018.012

DO - 10.2166/wst.2018.012

M3 - Article

VL - 77

SP - 1372

EP - 1385

JO - Progress in Water Technology

JF - Progress in Water Technology

SN - 0273-1223

IS - 5

ER -