Details
| Original language | English |
|---|---|
| Pages (from-to) | 575-589 |
| Number of pages | 15 |
| Journal | Meteorologische Zeitschrift |
| Volume | 21 |
| Issue number | 6 |
| Publication status | Published - Dec 2012 |
Abstract
Hong Kong is one of the most densely built-up and populated cities in the world. An adequate air ventilation at pedestrian level would ease the thermal stress in its humid subtropical climate, but the high-density city severely reduces the natural ventilation. This case study investigates pedestrian level ventilation in two neighbourhoods in Kowloon, downtown Hong Kong using the parallelized large-eddy-simulation (LES) model PALM. The LES technique is chosen here for a city quarter scale pedestrian comfort study despite of its high computational cost. The aims of the paper are a) to get a comprehensive overview of pedestrian level ventilation and a better understanding of the ventilation processes in downtown Hong Kong, b) to test the LES technique on this urban scale compared to the wind tunnel and c) to investigate how numerical/physical parameters influence ventilation. This case study is restricted to neutral stratification in order to allow a direct comparison with the wind tunnel. A sensitivity study quantifies the dependence of site-averaged ventilation on numerical and physical parameters and determines an appropriate urban LES set-up for two 1 km2 neighbourhoods in Kowloon (Tsim Sha Tsui, Mong Kok) that are investigated for prevailing E and SW wind. The results reveal the critical dependence of ventilation on the urban morphology. Air paths, street orientations, ground coverage, sites fronting the water, inter connectivity of spaces, building podium size and building heights can all affect the pedestrian wind environment. Isolated tall buildings may have a pronounced impact on ventilation both locally and downstream.
Keywords
- High-density city, Hong Kong, Pedestrian level ventilation, Urban large-eddy simulation, Wind environment
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Atmospheric Science
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In: Meteorologische Zeitschrift, Vol. 21, No. 6, 12.2012, p. 575-589.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - LES case study on pedestrian level ventilation in two neighbourhoods in Hong Kong
AU - Letzel, Marcus Oliver
AU - Helmke, Carolin
AU - Ng, Edward
AU - An, Xipo
AU - Lai, Alan
AU - Raasch, Siegfried
N1 - Financial support by a Chinese University of Hong Kong Social Science Panel Direct Grant, by the German Research Foundation (DFG) under grant RA 617/15-1/ 2 and by the German National Academic Exchange Ser- vice (DAAD) is gratefully acknowledged. GIS data of Hong Kong were provided by the HKSAR Planning Department under the project ‘‘Urban Climatic Map and Standards for Wind Environment’’. The simulations worth 1.4 M€ were performed on the North German su- percomputing center HLRN (www.hlrn.de). The authors are grateful to two anonymous reviewers who provided valuable comments.
PY - 2012/12
Y1 - 2012/12
N2 - Hong Kong is one of the most densely built-up and populated cities in the world. An adequate air ventilation at pedestrian level would ease the thermal stress in its humid subtropical climate, but the high-density city severely reduces the natural ventilation. This case study investigates pedestrian level ventilation in two neighbourhoods in Kowloon, downtown Hong Kong using the parallelized large-eddy-simulation (LES) model PALM. The LES technique is chosen here for a city quarter scale pedestrian comfort study despite of its high computational cost. The aims of the paper are a) to get a comprehensive overview of pedestrian level ventilation and a better understanding of the ventilation processes in downtown Hong Kong, b) to test the LES technique on this urban scale compared to the wind tunnel and c) to investigate how numerical/physical parameters influence ventilation. This case study is restricted to neutral stratification in order to allow a direct comparison with the wind tunnel. A sensitivity study quantifies the dependence of site-averaged ventilation on numerical and physical parameters and determines an appropriate urban LES set-up for two 1 km2 neighbourhoods in Kowloon (Tsim Sha Tsui, Mong Kok) that are investigated for prevailing E and SW wind. The results reveal the critical dependence of ventilation on the urban morphology. Air paths, street orientations, ground coverage, sites fronting the water, inter connectivity of spaces, building podium size and building heights can all affect the pedestrian wind environment. Isolated tall buildings may have a pronounced impact on ventilation both locally and downstream.
AB - Hong Kong is one of the most densely built-up and populated cities in the world. An adequate air ventilation at pedestrian level would ease the thermal stress in its humid subtropical climate, but the high-density city severely reduces the natural ventilation. This case study investigates pedestrian level ventilation in two neighbourhoods in Kowloon, downtown Hong Kong using the parallelized large-eddy-simulation (LES) model PALM. The LES technique is chosen here for a city quarter scale pedestrian comfort study despite of its high computational cost. The aims of the paper are a) to get a comprehensive overview of pedestrian level ventilation and a better understanding of the ventilation processes in downtown Hong Kong, b) to test the LES technique on this urban scale compared to the wind tunnel and c) to investigate how numerical/physical parameters influence ventilation. This case study is restricted to neutral stratification in order to allow a direct comparison with the wind tunnel. A sensitivity study quantifies the dependence of site-averaged ventilation on numerical and physical parameters and determines an appropriate urban LES set-up for two 1 km2 neighbourhoods in Kowloon (Tsim Sha Tsui, Mong Kok) that are investigated for prevailing E and SW wind. The results reveal the critical dependence of ventilation on the urban morphology. Air paths, street orientations, ground coverage, sites fronting the water, inter connectivity of spaces, building podium size and building heights can all affect the pedestrian wind environment. Isolated tall buildings may have a pronounced impact on ventilation both locally and downstream.
KW - High-density city
KW - Hong Kong
KW - Pedestrian level ventilation
KW - Urban large-eddy simulation
KW - Wind environment
UR - http://www.scopus.com/inward/record.url?scp=84874612934&partnerID=8YFLogxK
U2 - 10.1127/0941-2948/2012/0356
DO - 10.1127/0941-2948/2012/0356
M3 - Article
AN - SCOPUS:84874612934
VL - 21
SP - 575
EP - 589
JO - Meteorologische Zeitschrift
JF - Meteorologische Zeitschrift
SN - 0941-2948
IS - 6
ER -