Numerical simulation of wind environment in Xiamen east sea area

Abstract

This paper studies the urban wind environment in the inner bay area of Xiamen through numerical simulation, and provides wind field characteristics support for the construction of the new cross-sea bridge “Xiamen Third East Passage.” A circular computational domain with a diameter of 20 km was constructed, where the surface types were finely divided based on satellite maps and low-rise building distribution characteristics. Two scenarios with and without high-rise buildings were designed to explore the impact of building complexes on wind flow characteristics. In addition, a smaller computational domain with a diameter of 10 km was set up to evaluate the impact of the computational domain range on the simulation results. The results show that high-rise buildings increase roughness and reduce downstream wind speed. At a location about 1.67 times the building width downstream of the building complex, the wind speed recovered to 80% of the scenario without buildings, showing the significant interference of the building complex on the local wind field. Compared with the 20 km computational domain, the 10 km calculation results have large differences in the simulation results near the 240° and 300° wind directions, mainly because the smaller domain does not include building complex features, rather than the lack of geomorphic features. The lateral wind speed profile and roughness changes along the bridge site were also analyzed. The results showed that the wind field close to the land, especially in the Xiamen Island area, was relatively turbulent and the roughness coefficient increased significantly; while the wind field in the area far from the land was relatively stable, and the roughness coefficient basically remained at around 0.1.