ABSTRACT
Most previous studies of wind-driven rain (WDR) on buildings focused on WDR impact. Relatively little attention has been given to the contact and surface phenomena that occur after impact of raindrops, including runoff, absorption and evaporation. This paper presents a combination of two models to study both the impact and the contact and surface phenomena of rainwater on a glass window surface: a Computational Fluid Dynamics (CFD) model for the calculation of the direct WDR impact and a semi-empirical droplet-behavior model. The CFD model comprises the calculation of the wind-flow pattern, the raindrop trajectories and the specific catch ratio as a measure of the WDR falling onto different parts of the facade. The droplet-behavior model uses the output of the CFD model to simulate the behavior of individual raindrops on the window glass surface. The models are applied for WDR on a small window glass surface of a two-storey house.
