The Experts below are selected from a list of 2760 Experts worldwide ranked by ideXlab platform
Jianlei Niu - One of the best experts on this subject based on the ideXlab platform.
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Adopting 'lift-up' building design to improve the surrounding pedestrian-level wind environment.
Building and environment, 2017Co-Authors: Kimtim Tse, Cheuk Ming Mak, Kenny C. S Kwok, Xuelin Zhang, A.u. Weerasuriya, Jianlei NiuAbstract:Abstract Modern megacities are teeming with closely-spaced tall buildings, which limit air circulation at the pedestrian level. The resultant lack of air circulation creates poorly ventilated areas with accumulated air pollutants and thermal disComfort in the summer. To improve air circulation at the pedestrian level, buildings may be designed to have a ‘lift-up’ shape, in which the main structure is supported by a central core, columns or shear walls. However, a lack of knowledge on the influence of the ‘lift-up’ design on the surrounding wind environment limits the use of ‘lift-up’ buildings. This study aims to investigate the influence of ‘lift-up’ buildings and their dimensions on the pedestrian-level wind environments using wind tunnel tests. A parametric study was undertaken by using 9 ‘lift-up’ building models with different core heights and widths. The results were compared with the surrounding wind environment of a control building with similar dimensions. The results reveal that the ‘lift-up’ core height is the most influential parameter and governs the area and magnitude of high and low wind speed zones around such buildings. Based on wind tunnel test results and a selected Comfort Criterion, appropriate core dimensions could be selected to have acceptable wind conditions near lift-up buildings.
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New criteria for assessing low wind environment at pedestrian level in Hong Kong
Building and Environment, 2017Co-Authors: Cheuk Ming Mak, Kenny C. S Kwok, Kam Tim Tse, Tsz-cheung Lee, Jianlin Liu, Jianlei NiuAbstract:Abstract The choice of proper wind Comfort Criterion is considered to be crucial to reliable assessment of pedestrian level wind Comfort. This paper aims to propose a wind Comfort Criterion that can be applied to Hong Kong, in which the wind Comfort is seriously deteriorated by the moderated airflow, particularly in the hot and humid summer. By thoroughly reviewing and comparing exiting wind Comfort criteria, the parameters in Lawson (1978) Criterion are adopted for acceptable, tolerable and intolerable category and the parameters in NEN8100 (2006) Criterion are adopted for danger category in the proposed criteria. Besides, a low wind parameter suggested by AVA scheme (2005) is adopted for unfavourable category in summer Criterion. The adopted parameters provide scientific foundations and they are carefully chosen to adapt the weak wind conditions. The prominent features of the criteria are proposed seasonally (summer and winter, respectively) and the overall mean wind velocity ratio ( O M V R ) is used as threshold wind velocity parameter. The wind tunnel tests of Hong Kong Polytechnic University (HKPolyU) campus model were used as a case study. The results show that the proposed criteria can reasonably represent the weak wind condition and provide suitable assessments of the wind Comfort in Hong Kong. Moreover, the findings in this study provide scientific basis for future policy-making and the proposed criteria can also help city planners to improve the pedestrian level wind Comfort.
Van Taj Twan Hooff - One of the best experts on this subject based on the ideXlab platform.
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pedestrian wind Comfort around buildings comparison of wind Comfort criteria based on whole flow field data for a complex case study
Building and Environment, 2013Co-Authors: W Wendy D Janssen, Bje Bert Blocken, Van Taj Twan HooffAbstract:Abstract Assessment of pedestrian wind Comfort around buildings requires the combination of wind statistics from a meteorological station, aerodynamic information and a Comfort Criterion. A wide range of different Comfort criteria exist. In the past, several comparison studies of Comfort criteria have been made. In the present paper, a different approach is pursued. The goal of this paper is threefold: (1) to provide an illustrative case study based on CFD as a framework for the comparison of different criteria; (2) to compare and evaluate the results by the different criteria as part of a complete wind Comfort assessment study; and (3) to stress the importance of standardization of the wind Comfort assessment procedure. The case study area is the campus of Eindhoven University of Technology. The 3D steady Reynolds-averaged Navier–Stokes (RANS) equations and the realizable k – ɛ model are used to provide part of the aerodynamic information. The CFD simulations are performed on a high-resolution grid based on grid-sensitivity analysis. Validation is conducted with on-site measurements. Part of the wind Comfort assessment procedure is performed with the Dutch wind nuisance standard NEN 8100. The criteria compared in this study are the four complete criteria by Isyumov and Davenport (1975), Lawson (1978), Melbourne (1978) and NEN 8100 (2006). It is shown that the different criteria can lead to very different conclusions about the wind Comfort. Because the outcome of wind Comfort studies is often decisive in granting building permits, this illustrates the importance of wind Comfort standardization, in particular concerning the Comfort Criterion.
Ajay Gairola - One of the best experts on this subject based on the ideXlab platform.
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A review on the study of urban wind at the pedestrian level around buildings
Journal of Building Engineering, 2018Co-Authors: Hemant Mittal, Ashutosh Sharma, Ajay GairolaAbstract:Abstract Urbanization is leading towards the change of local wind climate in the vicinity of tall buildings , which influences the pedestrian level wind environment to an unComfortable or even dangerous level. Therefore nowadays, building design should not be limited only for the consideration of wind load and indoor environment, but outdoor wind environment should also be considered. This study presents a review of the methods for the assessment of pedestrian level wind climate, different wind Comfort Criterion and various techniques to evaluate the wind speed at the pedestrian level. In later sections, brief review for the influence of different parameters related to building design and configuration on pedestrian level wind is presented. After analyzing previous literature it is suggested that there is a strong need for the homogenization of different wind Comfort Criterion, as it may lead to different consequences for the architects. Among various wind tunnel measurement techniques, use of Irwin probe is simple and accurate compared to hot-wire anemometry and it can be installed at numerous locations for simultaneous measurement of pedestrian level wind speed. For numerical simulation, Reynolds Averaged Navier Stokes based technique has been used by various researchers, although this technique is not accurate as much as large eddy simulation and detached eddy simulation . But this technique is cost effective and requires less computing resources.
Cheuk Ming Mak - One of the best experts on this subject based on the ideXlab platform.
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Adopting 'lift-up' building design to improve the surrounding pedestrian-level wind environment.
Building and environment, 2017Co-Authors: Kimtim Tse, Cheuk Ming Mak, Kenny C. S Kwok, Xuelin Zhang, A.u. Weerasuriya, Jianlei NiuAbstract:Abstract Modern megacities are teeming with closely-spaced tall buildings, which limit air circulation at the pedestrian level. The resultant lack of air circulation creates poorly ventilated areas with accumulated air pollutants and thermal disComfort in the summer. To improve air circulation at the pedestrian level, buildings may be designed to have a ‘lift-up’ shape, in which the main structure is supported by a central core, columns or shear walls. However, a lack of knowledge on the influence of the ‘lift-up’ design on the surrounding wind environment limits the use of ‘lift-up’ buildings. This study aims to investigate the influence of ‘lift-up’ buildings and their dimensions on the pedestrian-level wind environments using wind tunnel tests. A parametric study was undertaken by using 9 ‘lift-up’ building models with different core heights and widths. The results were compared with the surrounding wind environment of a control building with similar dimensions. The results reveal that the ‘lift-up’ core height is the most influential parameter and governs the area and magnitude of high and low wind speed zones around such buildings. Based on wind tunnel test results and a selected Comfort Criterion, appropriate core dimensions could be selected to have acceptable wind conditions near lift-up buildings.
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New criteria for assessing low wind environment at pedestrian level in Hong Kong
Building and Environment, 2017Co-Authors: Cheuk Ming Mak, Kenny C. S Kwok, Kam Tim Tse, Tsz-cheung Lee, Jianlin Liu, Jianlei NiuAbstract:Abstract The choice of proper wind Comfort Criterion is considered to be crucial to reliable assessment of pedestrian level wind Comfort. This paper aims to propose a wind Comfort Criterion that can be applied to Hong Kong, in which the wind Comfort is seriously deteriorated by the moderated airflow, particularly in the hot and humid summer. By thoroughly reviewing and comparing exiting wind Comfort criteria, the parameters in Lawson (1978) Criterion are adopted for acceptable, tolerable and intolerable category and the parameters in NEN8100 (2006) Criterion are adopted for danger category in the proposed criteria. Besides, a low wind parameter suggested by AVA scheme (2005) is adopted for unfavourable category in summer Criterion. The adopted parameters provide scientific foundations and they are carefully chosen to adapt the weak wind conditions. The prominent features of the criteria are proposed seasonally (summer and winter, respectively) and the overall mean wind velocity ratio ( O M V R ) is used as threshold wind velocity parameter. The wind tunnel tests of Hong Kong Polytechnic University (HKPolyU) campus model were used as a case study. The results show that the proposed criteria can reasonably represent the weak wind condition and provide suitable assessments of the wind Comfort in Hong Kong. Moreover, the findings in this study provide scientific basis for future policy-making and the proposed criteria can also help city planners to improve the pedestrian level wind Comfort.
Kenny C. S Kwok - One of the best experts on this subject based on the ideXlab platform.
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Adopting 'lift-up' building design to improve the surrounding pedestrian-level wind environment.
Building and environment, 2017Co-Authors: Kimtim Tse, Cheuk Ming Mak, Kenny C. S Kwok, Xuelin Zhang, A.u. Weerasuriya, Jianlei NiuAbstract:Abstract Modern megacities are teeming with closely-spaced tall buildings, which limit air circulation at the pedestrian level. The resultant lack of air circulation creates poorly ventilated areas with accumulated air pollutants and thermal disComfort in the summer. To improve air circulation at the pedestrian level, buildings may be designed to have a ‘lift-up’ shape, in which the main structure is supported by a central core, columns or shear walls. However, a lack of knowledge on the influence of the ‘lift-up’ design on the surrounding wind environment limits the use of ‘lift-up’ buildings. This study aims to investigate the influence of ‘lift-up’ buildings and their dimensions on the pedestrian-level wind environments using wind tunnel tests. A parametric study was undertaken by using 9 ‘lift-up’ building models with different core heights and widths. The results were compared with the surrounding wind environment of a control building with similar dimensions. The results reveal that the ‘lift-up’ core height is the most influential parameter and governs the area and magnitude of high and low wind speed zones around such buildings. Based on wind tunnel test results and a selected Comfort Criterion, appropriate core dimensions could be selected to have acceptable wind conditions near lift-up buildings.
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New criteria for assessing low wind environment at pedestrian level in Hong Kong
Building and Environment, 2017Co-Authors: Cheuk Ming Mak, Kenny C. S Kwok, Kam Tim Tse, Tsz-cheung Lee, Jianlin Liu, Jianlei NiuAbstract:Abstract The choice of proper wind Comfort Criterion is considered to be crucial to reliable assessment of pedestrian level wind Comfort. This paper aims to propose a wind Comfort Criterion that can be applied to Hong Kong, in which the wind Comfort is seriously deteriorated by the moderated airflow, particularly in the hot and humid summer. By thoroughly reviewing and comparing exiting wind Comfort criteria, the parameters in Lawson (1978) Criterion are adopted for acceptable, tolerable and intolerable category and the parameters in NEN8100 (2006) Criterion are adopted for danger category in the proposed criteria. Besides, a low wind parameter suggested by AVA scheme (2005) is adopted for unfavourable category in summer Criterion. The adopted parameters provide scientific foundations and they are carefully chosen to adapt the weak wind conditions. The prominent features of the criteria are proposed seasonally (summer and winter, respectively) and the overall mean wind velocity ratio ( O M V R ) is used as threshold wind velocity parameter. The wind tunnel tests of Hong Kong Polytechnic University (HKPolyU) campus model were used as a case study. The results show that the proposed criteria can reasonably represent the weak wind condition and provide suitable assessments of the wind Comfort in Hong Kong. Moreover, the findings in this study provide scientific basis for future policy-making and the proposed criteria can also help city planners to improve the pedestrian level wind Comfort.