Effect of turbulence modeling schemes on wind-driven rain deposition on a mid-rise building: CFD modeling and validation

Quantification of wind-driven rain (WDR) is important for designing building envelope to minimize moisture-related issues. With advancements in Computational Fluid Dynamics (CFD) modeling, it is becoming a more readily accepted tool for WDR studies. The current study focuses on validation of CFD modeling of WDR on a midrise building. The accuracy of WDR modeling is dependent upon the accurate wind flow modeling. The influence of turbulence modeling on wind flow around and WDR deposition on a six-story building is investigated. Three turbulence models, Realizable k-epsilon, Standard k-omega, and k-omega SST along with log-law and power-law inlet velocity profiles, are studied. Wind-tunnel measurements were carried out to validate wind flow simulations. WDR simulation results are compared to full-scale field measurements. It is shown that stand-alone building solution to such simulations is possible and, in some cases, recommended. Wind around the surrounded building is altered on a 5% margin by the choice of turbulence scheme. Standard k-co with log-law inlet velocity profile, having wind and WDR at 20% and 25% average error range, performs the best on a stand-alone building. However, the influence of turbulence model and inlet velocity profile on WDR simulation is negligible for the surrounded building.