Parameterised drag model for the underlying surface roughness of buildings in urban wind environment simulation

2021 ◽  
pp. 108651
Author(s):  
M.Y. Fan ◽  
W.J. Li ◽  
X.L. Luo ◽  
Q.X. Shui ◽  
L.Z. Jing ◽  
...  
2013 ◽  
Vol 397-400 ◽  
pp. 2420-2425
Author(s):  
Shi Ling Chen ◽  
Jun Lu ◽  
Wei Wei Yu ◽  
Shao Liang Zhang

In order to solve the problems in complex terrain modeling by computational fluid dynamics(CFD) simulation at prophase, such as difficulty in collecting data, tedious modeling process, wasting times and so on. In this paper, combined various commonly digital technology,and the transformation between the network terrain file and CFD (PHOENICS) solid model is realized by using a new set of outdoor complex terrain rapid digital modeling method. Take mountain city -Chongqing as an object to analyses the near-surface wind environment. The method is directly generated by the network terrain data without any screening or simplified. The virtual model can be matched the actual terrain with the extreme. By using the simulation cycle for complex terrain, time will be greatly shortened for urban planning.


2014 ◽  
Vol 933 ◽  
pp. 329-334
Author(s):  
Ying Ming Su ◽  
Hsin Yao Huang

Architectural typology and configurations on the urban wind environment are closely related, this research took the large-scaled high-density development in Taiwan of Fujhou Affordable Housing as a case study, the use of computer simulation Ecotect Analysis, for collection of air distribution to explore central courtyard buildings wind environment flow in the urban environment for congregate housing. This study according to simulation results tried to adjust the configuration program for a further amendment to meet pedestrians comfort. Results proved that the use of computer simulation for design review, could effectively achieve the most optimized design while also to reduce energy conservation and improve comfort, which will further as references for future architectural design and master planning.


2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Meichun Cao ◽  
Zhaohui Lin

In this paper, the impact of urban surface roughness lengthz0parameterization scheme on the atmospheric environment simulation over Beijing has been investigated through two sets of numerical experiments using the Weather Research and Forecasting model coupled with the Urban Canopy Model. For the control experiment (CTL), the urban surfacez0parameterization scheme used in UCM is the model default one. For another experiment (EXP), a newly developed urban surfacez0parameterization scheme is adopted, which takes into account the comprehensive effects of urban morphology. The comparison of the two sets of simulation results shows that all the roughness parameters computed from the EXP run are larger than those in the CTL run. The increased roughness parameters in the EXP run result in strengthened drag and blocking effects exerted by buildings, which lead to enhanced friction velocity, weakened wind speed in daytime, and boosted turbulent kinetic energy after sunset. Thermal variables (sensible heat flux and temperature) are much less sensitive toz0variations. In contrast with the CTL run, the EXP run reasonably simulates the observed nocturnal low-level jet. Besides, the EXP run-simulated land surface-atmosphere momentum and heat exchanges are also in better agreement with the observation.


Author(s):  
Xingbo Yao ◽  
Shuo Han ◽  
Bart Dewancker

Using wind speed, wind direction, and turbulence intensity values as evaluation indicators, the ventilation performance of villages with complex building layouts was studied. We used the SKE, RNG, and RKE solvers in CFD-3D steady-state Reynolds-averaged Navier–Stokes (RANS) to simulate the wind environment of a village. The findings show that for the simulation of rural wind environments with complex building layouts, steady-state simulation solvers need to be evaluated in detail to verify their accuracy. In this study, a village with a complex architectural layout in Southern Shaanxi, China, was taken as the research object, and three steady-state simulation solvers were used to evaluate the ventilation performance of the village. The simulated data were compared with the measured data to find the most suitable solver for this kind of village wind environment simulation. The results show that for the simulation of the village wind environment with a complex building layout, the RNG simulation results have the lowest reliability among the three steady-state solvers. The reliability of wind speed distribution and turbulence intensity distribution are 0.7881 and 0.2473, respectively. However, the wind speed and turbulence intensity values obtained by the SKE solver are the closest to the measured values, which are 0.8625 and 0.9088, respectively. Therefore, for villages with complex building layouts, the SKE solver should be the first choice for simulating wind environment distribution. When using the RNG solver, the overall turbulence intensity value obtained is higher than the measured value. The average deviation between the simulated data and SKE and RKE at a height of 1.7 m is 42.61%. The main reason for this is that RNG overestimates the vortices and underestimates the airflow rate in the building intervals.


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