The University of Southampton
University of Southampton Institutional Repository

Numerical Simulations of Boundary-Layer Airflow Over Pitched-Roof Buildings

Numerical Simulations of Boundary-Layer Airflow Over Pitched-Roof Buildings
Numerical Simulations of Boundary-Layer Airflow Over Pitched-Roof Buildings

Arrays of buildings with pitched roofs are common in urban and suburban areas of European cities. Large-eddy simulations are performed to predict the boundary-layer flows over flat and pitched-roof cuboids to gain a greater understanding of the impact of pitched roofs on urban boundary layers. The simulation methodology is validated for an array of flat roof cuboids. Further simulations show that changes in the type of grid conformity have a negligible effect on the mean flow field and turbulent stresses, while having a visible, but small, effect on the dispersive stresses for a given packing density. Comparisons are made for flat and 45 pitched roof cuboid arrays at packing densities of 16.7% and 33.3%. The interactions between pitched-roof buildings and their effect on the urban boundary layer are considerably different to those of flat-roof buildings. The pitched roofs at a packing density of 33.3% leads to significant changes in the mean flow field, the Reynolds stresses, and the aerodynamic drag. Further work investigates the effects of changes in turbulence level and atmospheric thermal stratification in the approaching flow. Importantly, in comparison to a flat-roof array, the pitched-roof one at a packing density of 33.3% evidently increase the friction velocity and greatly reduces the effects of stable stratification conditions and changes in inflow turbulence level.

Atmospheric thermal stratification, Cartesian mesh, Drag coefficient, Packing density, Pitched roof, Spatial-average
0006-8314
415-442
Coburn, Matthew
ecfc4094-fdce-4076-afa7-e2c65fa13040
Xie, Zheng-Tong
98ced75d-5617-4c2d-b20f-7038c54f4ff0
Herring, Steven
15f891b4-1a9e-4ac8-af74-ce4158274451
Coburn, Matthew
ecfc4094-fdce-4076-afa7-e2c65fa13040
Xie, Zheng-Tong
98ced75d-5617-4c2d-b20f-7038c54f4ff0
Herring, Steven
15f891b4-1a9e-4ac8-af74-ce4158274451

Coburn, Matthew, Xie, Zheng-Tong and Herring, Steven (2022) Numerical Simulations of Boundary-Layer Airflow Over Pitched-Roof Buildings. Boundary-Layer Meteorology, 185 (3), 415-442. (doi:10.1007/s10546-022-00738-1).

Record type: Article

Abstract

Arrays of buildings with pitched roofs are common in urban and suburban areas of European cities. Large-eddy simulations are performed to predict the boundary-layer flows over flat and pitched-roof cuboids to gain a greater understanding of the impact of pitched roofs on urban boundary layers. The simulation methodology is validated for an array of flat roof cuboids. Further simulations show that changes in the type of grid conformity have a negligible effect on the mean flow field and turbulent stresses, while having a visible, but small, effect on the dispersive stresses for a given packing density. Comparisons are made for flat and 45 pitched roof cuboid arrays at packing densities of 16.7% and 33.3%. The interactions between pitched-roof buildings and their effect on the urban boundary layer are considerably different to those of flat-roof buildings. The pitched roofs at a packing density of 33.3% leads to significant changes in the mean flow field, the Reynolds stresses, and the aerodynamic drag. Further work investigates the effects of changes in turbulence level and atmospheric thermal stratification in the approaching flow. Importantly, in comparison to a flat-roof array, the pitched-roof one at a packing density of 33.3% evidently increase the friction velocity and greatly reduces the effects of stable stratification conditions and changes in inflow turbulence level.

Text
BLM2021_Pitched_Roof_15_nov - Accepted Manuscript
Download (2MB)
Text
s10546-022-00738-1 - Version of Record
Available under License Creative Commons Attribution.
Download (2MB)

More information

Submitted date: 15 November 2021
Accepted/In Press date: 26 July 2022
e-pub ahead of print date: 23 August 2022
Published date: December 2022
Additional Information: Funding Information: This research is mainly funded by a studentship of the Faculty of Engineering and the Environment. MC thanks Dr Tim Foat from the Defence Science and Technology Laboratory (Dstl) for providing insight and support. The authors thank the three anonymous peer reviewers for their very valuable comments and suggestions. Computational work has been undertaken on Southampton University’s Iridis systems. The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. Funding Information: This research is mainly funded by a studentship of the Faculty of Engineering and the Environment. MC thanks Dr Tim Foat from the Defence Science and Technology Laboratory (Dstl) for providing insight and support. The authors thank the three anonymous peer reviewers for their very valuable comments and suggestions. Computational work has been undertaken on Southampton University’s Iridis systems. The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. Publisher Copyright: © 2022, The Author(s).
Keywords: Atmospheric thermal stratification, Cartesian mesh, Drag coefficient, Packing density, Pitched roof, Spatial-average

Identifiers

Local EPrints ID: 452766
URI: http://eprints.soton.ac.uk/id/eprint/452766
ISSN: 0006-8314
PURE UUID: 2f0cb0ae-cf09-4965-a830-e5e1c62b8a6d
ORCID for Zheng-Tong Xie: ORCID iD orcid.org/0000-0002-8119-7532

Catalogue record

Date deposited: 20 Dec 2021 17:32
Last modified: 26 Jan 2023 05:01

Export record

Altmetrics

Contributors

Author: Matthew Coburn
Author: Zheng-Tong Xie ORCID iD
Author: Steven Herring

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×