Influence of urban environment on wind-driven rain load on building facades

Abstract

Wind-driven rain (WDR) is the largest moisture source that influences the hygrothermal performance of building envelopes. Accurate estimation of WDR load on building facades is very important for hygrothermal analysis of building envelopes. In this study, we use CFD models to investigate the influence of urban environment on WDR load and distribution on the building facades. The case study is a historical building located in the city center of Zurich. There is a very large difference between the WDR load and distribution on the building façade of the historical building when located in the urban environment or in the open field. For the same building, the WDR load can be five times larger in the open field than when located in an urban environment. Furthermore, the distribution pattern of WDR is also significantly changed by the presence of an urban environment. The decrease in WDR for the building in an urban environment is mainly due the reduction of the wind flow velocity especially in front of the historical building. Wind flow direction is significantly changed in the urban environment. Furthermore, compared to the CFD method, the empirical methods could be very inaccurate.Peer-review under the responsibility of the organizing committee of the ICMB21.