Building drag and shielding in a realistic urban environment
File(s)
Published version
Author(s)
Huang, Jingzi
Coceal, Omduth
Placidi, Marco
Xie, Zheng-Tong
van Reeuwijk, Maarten
Type
Journal Article
Abstract
Shielding by upstream buildings is a fundamental control on urban drag, yet its influence remains poorly quantified in realistic urban environments. Here, we investigate shielding effects using building-resolved large-eddy simulations of the University of Bristol campus, comprising 110 buildings of varying height, shape and orientation. Twenty-four wind directions are considered, allowing each building to experience a wide range of upstream shielding conditions. While the total drag of the campus exhibits only moderate directional variability, the drag acting on individual buildings varies substantially. In the present case, approximately 20% of buildings account for 80% of the total drag, which is primarily attributed to a small number of large buildings that contribute disproportionately high drag forces. To quantify shielding, we introduce two dimensionless parameters: the upstream fetch ratio, Ls / Hs, and the relative height ratio, Hs / H, where Ls is the distance to the nearest upstream obstacle, Hs is the height of the upstream obstacle, and H is the height of the target building. These parameters distinguish between near- and far-wake conditions and between sheltered and exposed buildings, providing a simple method to characterise shielding effects in realistic urban environments. The study provides valuable quantitative insight into drag and shielding in the Bristol campus morphology; more importantly, it establishes a general framework for analysing drag and shielding that can be applied in other complex urban environments. The results identify shielding as a primary control on building drag and motivate shielding-aware measures of effective frontal area and drag coefficient.
Date Issued
2026-11-01
Date Acceptance
2026-08-17
Citation
Journal of Wind Engineering and Industrial Aerodynamics, 2026, 278
ISSN
0167-6105
Publisher
Elsevier BV
Journal / Book Title
Journal of Wind Engineering and Industrial Aerodynamics
Volume
278
Copyright Statement
© 2026 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Publication Status
Published
Article Number
106612
Date Publish Online
2026-08-27