CFD modeling of Wind-Driven Rain (WDR) on a mid-rise building in an urban area

Abstract

Wind-Driven Rain (WDR) loading on building facades is a crucial factor for designing sustainable and climate-resilient buildings and preserving historical buildings. WDR loading on buildings has been studied previously but results for such a multi-parameter problem are not generally conclusive. Thus, the relevant provisions of ISO semi-empirical model cannot be applied with confidence for complex building configurations, such as those in urban areas given that the estimated WDR can be more than twice of the field measurements. This paper aims to evaluate the effectiveness of two WDR techniques, namely Lagrangian Particle Tracking (LPT) and Eulerian Multiphase (EM), combined with the steady-state standard k-ω RANS turbulence model (referred to as RANS-LPT and RANS-EM). The results obtained from the RANS-EM approach are compared with the RANS-LPT results reported in the literature for a six-story mid-rise residential building located in Vancouver, Canada. The study considers 13 distinct rainfall events, including stand-alone and urban area configurations with and without overhangs. The RANS-EM and RANS-LPT approaches are evaluated by comparing modeled wind and WDR against wind-tunnel and on-site WDR measurements, respectively. The study found that the RANS-EM requires less computational time and provides more accurate results for the test building situated in an urban area compared to the RANS-LPT.