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Aerodynamic parameters of urban building arrays with random geometries

It is difficult to describe the flow characteristics within and above urban canopies using only geometrical parameters such as plan area index (λp) and frontal area index (λf) because urban surfaces comprise buildings with random layouts, shapes, and heights. Furthermore, two types of 'randomne...

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Main Authors: Shaikh Salim, Sheikh Ahmad Zaki, Hagishima, Aya, Tanimoto, Jun, Ikegaya, Naoki
Format: Article
Published: Springer Netherlands 2011
Subjects:
TH Building construction
Online Access:http://eprints.utm.my/id/eprint/44717/
http://dx.doi.org/10.1007/s10546-010-9551-7
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spelling my.utm.447172022-02-08T01:57:30Z http://eprints.utm.my/id/eprint/44717/ Aerodynamic parameters of urban building arrays with random geometries Shaikh Salim, Sheikh Ahmad Zaki Hagishima, Aya Tanimoto, Jun Ikegaya, Naoki TH Building construction It is difficult to describe the flow characteristics within and above urban canopies using only geometrical parameters such as plan area index (λp) and frontal area index (λf) because urban surfaces comprise buildings with random layouts, shapes, and heights. Furthermore, two types of 'randomness' are associated with the geometry of building arrays: the randomness of element heights (vertical) and that of the rotation angles of each block (horizontal). In this study, wind-tunnel experiments were conducted on seven types of urban building arrays with various roughness packing densities to measure the bulk drag coefficient Cd and mean wind profile; aerodynamic parameters such as roughness length zo and displacement height d were also estimated. The results are compared with previous results from regular arrays having neither 'vertical' nor 'horizontal' randomness. In vertical random arrays, the plot of Cd and zo versus λf exhibited a monotonic increase, and zo increased by a factor of almost two for λf = 48-70%. Cd was strongly influenced by the standard deviation of the height of blocks (s) when λp = 17%, whereas Cd was independent of s when λp = 7%. In the case of horizontal random arrays, the plot of the estimated Cd against λf showed a peak. The effect of both vertical and horizontal randomness of the layout on aerodynamic parameters can be explained by the structure of the vortices around the blocks; the aspect ratio of the block is an appropriate index for the estimation of such features. Springer Netherlands 2011 Article PeerReviewed Shaikh Salim, Sheikh Ahmad Zaki and Hagishima, Aya and Tanimoto, Jun and Ikegaya, Naoki (2011) Aerodynamic parameters of urban building arrays with random geometries. Boundary-Layer Meteorology, 138 . pp. 99-120. ISSN 0006-8314 http://dx.doi.org/10.1007/s10546-010-9551-7 DOI:10.1007/s10546-010-9551-7
institution Universiti Teknologi Malaysia
building UTM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Teknologi Malaysia
content_source UTM Institutional Repository
url_provider http://eprints.utm.my/
topic TH Building construction
spellingShingle TH Building construction
Shaikh Salim, Sheikh Ahmad Zaki
Hagishima, Aya
Tanimoto, Jun
Ikegaya, Naoki
Aerodynamic parameters of urban building arrays with random geometries
description It is difficult to describe the flow characteristics within and above urban canopies using only geometrical parameters such as plan area index (λp) and frontal area index (λf) because urban surfaces comprise buildings with random layouts, shapes, and heights. Furthermore, two types of 'randomness' are associated with the geometry of building arrays: the randomness of element heights (vertical) and that of the rotation angles of each block (horizontal). In this study, wind-tunnel experiments were conducted on seven types of urban building arrays with various roughness packing densities to measure the bulk drag coefficient Cd and mean wind profile; aerodynamic parameters such as roughness length zo and displacement height d were also estimated. The results are compared with previous results from regular arrays having neither 'vertical' nor 'horizontal' randomness. In vertical random arrays, the plot of Cd and zo versus λf exhibited a monotonic increase, and zo increased by a factor of almost two for λf = 48-70%. Cd was strongly influenced by the standard deviation of the height of blocks (s) when λp = 17%, whereas Cd was independent of s when λp = 7%. In the case of horizontal random arrays, the plot of the estimated Cd against λf showed a peak. The effect of both vertical and horizontal randomness of the layout on aerodynamic parameters can be explained by the structure of the vortices around the blocks; the aspect ratio of the block is an appropriate index for the estimation of such features.
format Article
author Shaikh Salim, Sheikh Ahmad Zaki
Hagishima, Aya
Tanimoto, Jun
Ikegaya, Naoki
author_facet Shaikh Salim, Sheikh Ahmad Zaki
Hagishima, Aya
Tanimoto, Jun
Ikegaya, Naoki
author_sort Shaikh Salim, Sheikh Ahmad Zaki
title Aerodynamic parameters of urban building arrays with random geometries
title_short Aerodynamic parameters of urban building arrays with random geometries
title_full Aerodynamic parameters of urban building arrays with random geometries
title_fullStr Aerodynamic parameters of urban building arrays with random geometries
title_full_unstemmed Aerodynamic parameters of urban building arrays with random geometries
title_sort aerodynamic parameters of urban building arrays with random geometries
publisher Springer Netherlands
publishDate 2011
url http://eprints.utm.my/id/eprint/44717/
http://dx.doi.org/10.1007/s10546-010-9551-7
_version_ 1724607965011378176
score 13.211869

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