1. College of Civil Engineering, Chongqing University, Chongqing 400045, China 2. Key Laboratory of New Technology for Construction of Cities in Mountain Area, Chongqing University, Chongqing 400045, China
The large eddy simulation method was used to study the wind load characteristics of low-rise buildings under the action of unsteady thunderstorms. The following aspects were analyzed to study the influence on the wind load of the building in different development stages of the downburst: the radial position of the building, the roof slope and the wind direction angle, etc. Results show that there are significant differences in wind load effect at different development stages. When the first ring vortex generated by the airflow hitting the ground blows over the building, the wind load of the building is the most unfavorable. While the building is in different radial positions, the transient wind pressure caused by the ring vortex passing through the building is quite different from that caused by the steady downburst at the same position. The slope of roof has less influence on the distribution of wind pressure coefficient in the windward roof, but great influence on that in the windward side roof. When the slope of the roof increases, the wind pressure coefficient of the windward roof gradually changes from negative value to positive value. The wind pressure coefficient for the corner of the windward front of the building is obviously affected by the wind direction angle. In the tested condition, the influence is most significant when the wind direction angle is 45°.
Zhi-song WANG,Jun DENG,Zhi-yuan FANG,Yuan-yuan CHEN. Large eddy simulation of wind load on low-rise buildings subjected to downburst. Journal of ZheJiang University (Engineering Science), 2020, 54(3): 512-520.
Fig.1Schematic diagram of computational domain and boundary conditions of numerical model
Fig.2Schematic diagram of mesh generation
工况编号
i
r/m
θ/（°）
工况编号
i
r/m
θ/（°）
1
0.1
Djet
0
5
0.1
1.5Djet
0
2
0.4
Djet
0
6
0.1
2.0Djet
0
3
0.5
Djet
0
7
0.1
Djet
45
4
1
Djet
0
8
0.1
Djet
90
Tab.1Numerical simulation cases
Fig.3Arrangement and number of measurement points on building model surface
Fig.4Comparison of dimensionless wind profiles with different grid numbers
Fig.5Comparison of wind pressure coefficient of building surface under different cases
Fig.6Comparison of dimensionless vertical wind profiles
Fig.7Comparison of dimensionless radial wind profiles
Fig.8Time history of wind pressure coefficient of windward and cross-wind surface center
Fig.9Wind speed nephogram of longitudinal section and air streamline around building at different times of downburst development stage
Fig.10Distribution of mean wind pressure coefficient of roof in stage of development downburst
Fig.11Distribution of mean wind pressure coefficients of flat roof in downburst
Fig.12Pressure coefficients along centerline varied with slope value of model roof
Fig.13Distribution of mean wind pressure coefficient under influence of wind direction angle
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