CFD Wind Field Simulation On Kowloon Bay Coastal Town In Hong Kong And Wind Disaster Vulnerability Analysis

Along the coastal areas of China, the frequent typhoon causes great loss in cities. Typhoon disaster assessment has become an important part in the field of disaster presentation. Before assessment, we should have a clear understanding on wind field in urban environment. Computational Fluid Dynamics( CFD) provides technical support. Hong Kong, located in coastal areas of southern China, is perennially attacked by typhoon. This paper studies wind environment on Kowloon Bay coastal town, Hong Kong with the aid of CFD techniques and carries on wind disaster vulnerability analysis on cable-type billboard.Several measures are carried out to ensure accuracy of the simulation. Firstly, grid dependence analysis is made to obtain a reasonable meshing scheme which has a good balance between accuracy and efficiency. Subsequently, this paper puts forward a way to determine inlet wind profile. CFD simulation is performed in the upstream of computation domain, then parameters of inlet wind profile cloud be determined through logarithmic curve fitting. This method helps to acquire a good simulation result. Finally, by comparing several kinds of turbulence model and wall function, this paper considers that Realizable k ?? turbulence model and non-equilibrium wall function are applicable in mesoscale wind environment simulation in complex urban.The validation is performed in this paper through the comparison between CFD simulation result and data from field measurement. The validation shows that CFD simulation result is basically consistent with the actual wind field situation in Kowloon Bay coastal town. Therefore, we consider that the CFD simulation is credible.In this paper, the cable-type billboard serves as the research object of wind disaster vulnerability analysis. Through investigation, the structure and failure modes of cable-type billboard under wind load are shown in this paper. CFD wind simulation is performed in Hong Ning Block by general simulation method and multi-scale nested simulation method. The result shows that the wind environment of Hong Ning Block is greatly influenced by its surroundings, which further proves the necessity of mesoscale CFD simulation of urban wind environment. Through the wind environment CFD simulation on Hong Ning Block, the wind load of cable-type billboard is determined. Ultimately, Monte Carlo simulation is applied to acquire the relationship between wind speed and failure probability of cable-type billboard. Wind disaster vulnerability curve is plotted, from which reflects design defect in the billboard and this paper throws out some suggestions on strengthening measures.Urban construction has greatly changed the characteristics of original landscape, which makes that the surroundings of some field measurement stations no longer meet observational requirements. Meanwhile, it is difficult to fully reflect the distribution of urban wind field relying on a limited number of field measurement stations and it would cause large errors if observed maximum wind speed is used directly in disaster assessment. Urban wind environment CFD simulation is a good supplement to field measurement. The simulation result cloud be regarded as a database, having great reference value in wind disaster prevention work.