Impact of upstream fetch on environmental wind engineering applications

With the rapid urbanization process, there is a growing concern regarding the wind environment in suburban and urban regions. The purpose of this study is to investigate the influence of the upstream fetch length on environmental wind engineering issues, such as the pedestrian level wind (PLW) and the wind comfort assessment around newly built buildings. The suburban region of Westmount in Montreal and the urban area of Kowloon in Hong Kong are selected for case studies. The investigation has been experimental and results were obtained from two atmospheric boundary layer wind tunnels. The results indicate that the upstream fetch length that influences the PLW estimation in suburban areas is as short as 200 m and in urban areas is as short as 450 m. For the wind comfort assessment of a newly building, an upstream fetch length of 100 m from the building site can be utilized depending on the criteria used. •The minimum upstream fetch length impacts the PLW velocity is about 200 m in suburban exposure.•The assessment of wind comfort around a newly proposed buildings is less sensitive to upstream fetch length.•The minimum upstream fetch length impacts the wind comfort assessment is about 100 m in suburban exposure.•A 450 m upstream fetch length yields reliable results for PLW velocity estimation in urban exposure.