Numerical investigation of the wind environment around tall buildings in a central business district

doi:10.1007/s11707-019-0787-3

Front. Earth Sci.

2019, Vol. 13

Issue (4) : 848-858 https://doi.org/10.1007/s11707-019-0787-3

RESEARCH ARTICLE

Numerical investigation of the wind environment around tall buildings in a central business district

Pingzhi FANG¹(

), Deqian ZHENG², Ming GU³, Haifeng CHENG⁴, Bihong ZHU⁴

¹. Shanghai Typhoon Institute of China Meteorological Administration, Shanghai 200030, China
². School of Civil Engineering and Architecture, Henan University of Technology, Zhengzhou 450001, China
³. State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China
⁴. Shanghai Investigation, Design &Research Institute Co., Ltd., Shanghai 200335, China

Download: PDF(4818 KB) HTML
Export: BibTeX | EndNote | Reference Manager | ProCite | RefWorks

Abstract

The wind environment around tall buildings in a central business district (CBD) was numerically investigated. The district covers an area of ~4.0 km² and features a high density of tall buildings. In this study, only buildings taller than 20 m were considered, resulting in 173 tall buildings in the analysis. The numerical investigation was realized using the commercial computational fluid dynamics code FLUENT with the realizable $k − ε$ turbulence model. Special efforts were made to maintain inflow boundary conditions throughout the computational domain. The reliability of the numerical method was validated using results from an experimental investigation conducted in the core area of the CBD (~1.5 km²). Experimental and numerical investigations of wind speed ratios at the center of the three tallest buildings in the CBD agree within an uncertainty factor of 2.0. Both the experimental and numerical results show that wind speed ratios in the wind field with exposure category D are higher than those from the wind field with exposure category B. Based on the above validation work, the wind environment around tall buildings in the whole CBD was then investigated by numerical simulation. Common flow phenomena and patterns, such as stagnation points, shielding effects, separation flow, and channeling flow, were identified around the tall buildings. The pedestrian-level wind environment around tall buildings in the CBD was further evaluated using nearby meteorological wind data. The evaluation results show that some pedestrian activities, such as sitting at the center of the three tallest buildings, are unadvisable when the wind blows from the south-east.

Keywords wind environment pedestrian-level wind computational fluid dynamics wind speed ratio central business district

Corresponding Author(s): Pingzhi FANG

Just Accepted Date: 21 August 2019 Online First Date: 30 October 2019 Issue Date: 30 December 2019

Cite this article:

Pingzhi FANG,Deqian ZHENG,Ming GU, et al. Numerical investigation of the wind environment around tall buildings in a central business district[J]. Front. Earth Sci., 2019, 13(4): 848-858.

URL:

https://academic.hep.com.cn/fesci/EN/10.1007/s11707-019-0787-3
https://academic.hep.com.cn/fesci/EN/Y2019/V13/I4/848

Fig.1 (a) Location of the CBD and meteorological weather stations; (b) enlarged view of the CBD based on the Baidu map; and (c) buildings taller than 20 m in the CBD (AREA 2).

Fig.2 Experimental investigation of the wind environment around tall buildings in AREA 1.

Wind field			Model constant
Exposure category	$z 0$ /m	$z ′ 0$ /m	$C 2$	$σ ?$	$σ k$
B ( $α = 0.15$ )	0.0002638	—	1.9	1.2	0.4
D ( $α = 0.30$ )	0.006756	0.0003556	1.7	1.8	1.0

Tab.1 Model constants for the realizable

k − ?

turbulence model at 1:300 scale

Boundary	BC	Mathematical implication
Inlet	Velocity-Inlet	$U$ $U = 0.249 ln ? (z / z 0) / 0.42$
		$k$ ^a) $κ = − 0.0040 ln ? (z / z 0) + 0.0354$
		$?$ $? = C μ 1 / 2 k ∂ U / ∂ z$ , $C μ = 0.13$
Outlet	Pressure-Outlet	$k$ , $?$ : same as those at the inlet boundary
Top	Symmetry	$∂ (U, ? P, ? k, ? ?) / ∂ z = 0$
Side	Symmetry	$∂ (U, ? P, ? k, ? ?) / ∂ y = 0$
Building surface	Wall	Standard wall function (SWF): $K s = 0$
Land surface	Wall	Standard wall function (SWF): $K s = 6.5 z 0$

Tab.2 BCs for the wind field with exposure category B at 1:300 scale

Boundary	BC	Mathematical implication
Inlet	Velocity-Inlet	$U$ $U = 0.4018 ln ? ((z + z 0) / z 0) / 0.42$
		$k$ ^a) $k = − 0.013 ln ? ((z + z 0) / z 0) + 0.075$
		$?$ $? = C μ 1 / 2 k ∂ U / ∂ z$ , $C μ = 0.09$
Outlet	Pressure-Outlet	$k$ , $?$ : same as those at the inlet boundary
Top	Symmetry	$∂ (U, ? P, ? k, ? ?) / ∂ z = 0$
Side	Symmetry	$∂ (U, ? P, ? k, ? ?) / ∂ y = 0$
Building surface	Wall	Standard wall function (SWF): $K s = 0$
Land surface	Wall	User-defined WF with $δ B = 7.0$ and $K s = 6.5 z ′ 0$

Tab.3 BCs for the wind field with exposure category D at 1:300 scale

Fig.3 Comparisons of profiles of the prescribed inlet flow at the inlet boundary (

x = − 5.0 H

) and the approaching flow before the CBD (

x = − 3.75 H

), for wind fields with exposure categories B and D: (a) profiles of the mean wind speed; and (b) profiles of the turbulent kinetic energy.

Fig.4 Comparisons of the wind speed ratios between the wind tunnel and numerical results: (a) results from the wind field with exposure category B; and (b) results from the wind field with exposure category D.

Fig.5 Comparisons of the wind speed ratios between the wind fields with different exposure categories: (a) wind tunnel results; and (b) numerical results.

Fig.6 Numerical results on the variation of the wind speed ratios with height for the case N: (a) the whole profile; and (b) profile near the land surface.

Fig.7 (a) Aerodynamic shapes of the buildings and the mesh scheme on the land and building surfaces; (b) close view around the three tallest buildings.

Fig.8 Contours of wind speed ratios at the pedestrian level

h = 0.0067 m

(corresponding to a height of 2.0 m at full scale) for (a) case N; and (b) case SE.

Tab.4 Terrain-related transform factor

T

in each wind direction

Fig.9 Wind rose diagrams showing (a) speed; and (b) direction for the BSWS. Calm conditions is denoted ‘C’ and corresponds to wind speeds of<0.3 m/s; : maximum wind speed; : mean wind speed; :median wind speed; : mode wind speed; and : wind direction.

Tab.5 Comfort and safety criteria developed by ^{Soligo et al. (1998)}

Tab.6 Evaluation results for the pedestrian–level wind environment ^a)

1	B Blocken (2014). 50 years of computational wind engineering: past, present, and future. J Wind Eng Ind Aerodyn, 129: 69–102 https://doi.org/10.1016/j.jweia.2014.03.008
2	B Blocken , J Carmeliet (2008). Pedes trian wind conditions at outdoor platforms in a high-rise apartment building: generic sub-configuration validation, wind comfort assessment, and uncertainty issues. Wind Struct, 11(1): 51–70 https://doi.org/10.12989/was.2008.11.1.051
3	B Blocken , J Carmeliet, T Stathopoulos (2007a). CFD evaluation of wind speed conditions in passages between parallel buildings-effect of wall-function roughness modifications for the atmospheric boundary layer flow. J Wind Eng Ind Aerodyn, 95(9–11): 941–962 https://doi.org/10.1016/j.jweia.2007.01.013
4	B Blocken , T Stathopoulos (2013). CFD simulation of pedestrian-level wind conditions around buildings: past achievements and prospects. J Wind Eng Ind Aerodyn, 121: 138–145 https://doi.org/10.1016/j.jweia.2013.08.008
5	B Blocken , T Stathopoulos, J Carmeliet (2007b). CFD simulation of the atmospheric boundary layer: wall function problems. Atmos Environ, 41(2): 238–252 https://doi.org/10.1016/j.atmosenv.2006.08.019
6	B Blocken , T Stathopoulos, J P A J van Beeck (2016). Pedestrian-level wind conditions around buildings: review of wind-tunnel and CFD techniques and their accuracy for wind comfort assessment. Build Environ, 100: 50–81 https://doi.org/10.1016/j.buildenv.2016.02.004
7	M Cindori , F Juretic, H Kozmar, I Dzijan (2018). Steady RANS model of the homogeneous atmospheric boundary layer. J Wind Eng Ind Aerodyn, 173: 289–301 https://doi.org/10.1016/j.jweia.2017.12.006
8	P Fang, M Gu, J TAN, Z HAN (2015). A method to solve the wall function problem in simulating the atmospheric boundary layer. J Vibration Shock, 34(2): 85–90 (in Chinese)
9	J H Ferziger (1990). Approaches to turbulent flow computation: applications to flow over obstacles. J Wind Eng Ind Aerodyn, 35: 1–19 https://doi.org/10.1016/0167-6105(90)90208-T
10	GB50009–2012 (2012). National Standard of the People’s Republic of China: Load Code for the Design of Building Structures (in Chinese)
11	B A Harper, J D Kepert, J D Ginger (2009). Guidelines for converting between various windaveraging periods in tropical cyclone conditions. In: Sixth Tropical Cyclone RSMCs/TCWCs Technical Coordination Meeting Technical Document. Brisbane
12	J He, C C S Song (1999). Evaluation of pedestrian winds in urban area by numerical approach. J Wind Eng Ind Aerodyn, 81(1–3): 295–309 https://doi.org/10.1016/S0167-6105(99)00025-2
13	T Jitendra, M Zhao, T M Zhou, L Cheng (2014). Three-dimensional simulation of vortex shedding flow in the wake of a yawed circular cylinder near a plane boundary at a Reynolds number of 500. Ocean Eng, 87(1): 25–39
14	F Juretic, H Kozmar (2014). Computational modeling of the atmospheric boundary layer using various two-equation turbulence models. Wind Struct, 19(6): 687–708 https://doi.org/10.12989/was.2014.19.6.687
15	B E Launder, D B Spalding (1974). The numerical computation of turbulent flows. Comput Methods Appl Mech Eng, 3(2): 269–289 https://doi.org/10.1016/0045-7825(74)90029-2
16	S Murakami (1997). Current status and future trends in computational wind engineering. J Wind Eng In Aerod, 67: 3–34
17	A A Razak, A Hagishima, N Ikegaya, J Tanimoto (2013). Analysis of airflow over building arrays for assessment of urban wind environment. Build Environ, 59: 56–65 https://doi.org/10.1016/j.buildenv.2012.08.007
18	L Shen, Y Han, C S Cai, G C Dong, J R Zhang, P Hu (2017). LES of wind environments in urban residential areas based on an inflow turbulence generating approach. Wind Struct, 24(1): 1–24 https://doi.org/10.12989/was.2017.24.1.001
19	M J Soligo, P A Irwin, C J Williams, G D Schuyler (1998). A comprehensive assessment of pedestrian comfortincluding thermal effects. J Wind Eng In Aerod, 77(1): 753–766
20	T Stathopoulos, A Baskaran (1996). Computer simulation of wind environmental conditions around buildings. Eng Struct, 18(11): 876–885 https://doi.org/10.1016/0141-0296(95)00155-7
21	I C Tolias, N Koutsourakis, D Hertwig, G C Efthimiou, A G Venetsanos, J G Bartzis (2018). Large Eddy Simulation study on the structure of turbulent flow in a complex city. J Wind Eng Ind Aerodyn, 177: 101–116 https://doi.org/10.1016/j.jweia.2018.03.017
22	C W Tsang, K C S Kwok, P A Hitchcock (2012). Wind tunnel study of pedestrian level wind environment around tall buildings: effects of building dimensions, separation and podium. Build Environ, 49: 167–181 https://doi.org/10.1016/j.buildenv.2011.08.014
23	D G Vernay, B Raphael, I F C Smith (2015). Improving simulation predictions of wind around buildings using measurements through system identification techniques. Build Environ, 94(2): 620–631 https://doi.org/10.1016/j.buildenv.2015.10.018
24	E Willemsen, J A Wisse (2002). Accuracy of assessment of wind speed in the built environment. J Wind Eng Ind Aerod, 90(10): 1183–1190 https://doi.org/10.1016/S0167-6105(02)00231-3
25	X D Xu, Q S Yang, A Yoshida, Y Tamura (2017). Characteristics of pedestrian-level wind around super-tall buildings with various configurations. J Wind Eng Ind Aerod, 166: 61–73 https://doi.org/10.1016/j.jweia.2017.03.013
26	Y Yang, M Gu, S Q Chen, X Jin (2009). New inflow boundary conditions for modelling the neutral equilibrium atmospheric boundary layer in computational wind engineering. J Wind Eng Ind Aerod, 97(2): 88–95 https://doi.org/10.1016/j.jweia.2008.12.001
27	A Zhang, C Gao, L Zhang (2005). Numerical simulation of the wind field around different building arrangements. J Wind Eng Ind Aerod, 93(12): 891–904 https://doi.org/10.1016/j.jweia.2005.09.001
28	X Zhang, K T Tse, A U Weerasuriya, K C S Kwok, J Niu, Z Lin, C M Mak (2018). Pedestrian-level wind conditions in the space underneath lift-up buildings. J Wind Eng Ind Aerod, 179: 58–69 https://doi.org/10.1016/j.jweia.2018.05.015
29	C R Zheng, Y S Li, Y Wu (2016). Pedestrian-level wind environment on outdoor platforms of a thousand-meter-scale megatall building: sub-configuration experiment and wind comfort assessment. Build Environ, 106(9): 313–326 https://doi.org/10.1016/j.buildenv.2016.07.004

Viewed

Full text

Abstract

Cited

Shared

Discussed