Numerical study on influence of surface vegetation on aerodynamics of high-rise buildings

Abstract

Vegetation on the surface of buildings is becoming popular in modern society. Besides their environmental and visual effect, vegetation can also affect the flow around them. In this study, the impact of surface planted trees on the aerodynamics of high-rise buildings under atmospheric boundary flow is investigated. Large eddy simulation is employed for the quantitative study. The results indicate that fluctuating lift force of building with both continuous ribs and fully planted trees can be 15.3% lower than that with ribs only. A closer examination on the model's surface pressure indicates that trees primarily decrease the mean and fluctuating wind pressures on the model's sidewalls by up to 20% and 26%, respectively. The mean flow field shows the separation bubble of the models with trees are significantly compressed and pushed away from the side face. Such flow structure contributes to the reduction of mean pressure coefficient at the vortex core of the separation bubble and side faces comparing to the reference model. Additionally, results also show that trees can significantly reduce flow fluctuations near the side faces of model, which is responsible of reduction of the fluctuating wind pressure coefficients on the model surfaces.