Multi-Method Simulation Research Of Wind Environment In Urban Blocks Based On CFD

The sharply expansion of urban space and the rapid increase of urban population pose high challenges and requirements for the construction of a comfortable and pleasant urban environment.Urban wind environmental issues are getting more and more attention in this context.Appropriate urban ventilation can speed up the exchange of material and energy in the urban zone with the natural space,with positive significance to the mitigation of urban micro-climate and enhancement of residents' comfort.At present,Computational Fluid Dynamics(CFD)simulation technology is one of the important methods to study the urban wind environment.There are no unified conclusions in computational parameters selection such as the turbulence model in the simulation process.On the other hand,the treatment of low-rise buildings in the large-scale urban wind environment simulation also affects the accuracy of the simulation results to some extent.Based on the above issues,this paper carries out the following research.In order to combine the advantages of the traditional RANS and LES methods,this paper uses UDF programming to realize the numerical simulation of wind environment by the V2F/LES hybrid turbulence model,which is verified with wind tunnel test of a standard tall building model.On this basis,the paper takes the Wutong area of Wuyuanwan Bay in Xiamen city as the research object,simulating the wind environment by three method,namely explicit model method of all buildings,implicit model of low-rise buildings respectively based on additional stress source term method and specifying roughness length method.Then using the V2F/LES hybrid turbulence model and the standard ?-? turbulence model which is commonly used in engineering,to perform the simulation of two main wind direction in the target area by explicit model of all buildings.The results shows that the hybrid model can capture more details of the wake vortexes around the buildings.Other side,comparative analysis of the results of the two implicit model method find that,the frictional effect of the additional stress source term method(Based on UDF programming)is transmitted more clearly,and the specifying roughness length method's overall flow pattern is closer to the explicit model of all buildings.Finally,the specifying roughness length method is used to simulate the strong inflow of 8 wind directions in the area.Analysis of wind load distribution characteristics of a building points out that,the simulation result of 45 ° direction is most consistent with the investigation result of the "Meranti" typhoon on the damage of the building glass curtain wall in the area at that time.In summary,based on UDF self-programming,the hybrid turbulence model method is applied to the urban area wind environment simulation,and the applicability of the hybrid model is discussed.The simulation result by implicit model of low-rise buildings through specifying roughness length method is acceptable compared with the field survey data,this paper can provide some reference for other large-scale urban wind environment simulation.