Numerical Investigation On The Distribution Characteristics Of Wind-Driven Rain Action For Different Building Shapes

Wind-driven rain (WDR) is oblique rain with a horizontal velocity component due to the result of wind and rain in the vertical fall of raindrops. WDR impinging on the building facades can lead to a series of engineering problems, such as water penetration, frost damage, moisture-induced salt migration, wall crack and mold growth at interior wall surfaces. And it also leads to the destruction of building assembly and structural safety. In severe cases, the extreme weather has strengthened WDR’s destructive power over buildings. Therefore, it is quite necessary to conduct the research of the wind-driven rain (WDR) amount and its pressure distribution and obtain the distribution characteristics for different building shape, to reducing the disaster of wind and rain for buildings and provide the basis for related field.In this paper, governing equations for the phases of wind and rain were established based on the Eulerian multiphase model. The equations was solved in combination with the urbulence model to conduct the study of the distribution of WDR intensity and rain load for different building shapes. Firstly, WDR field is simulated for a low and flat roof building combining with the actual measurement data by virture of the Eulerian multiphase model, and three turbulence model are adopted respectively, verifying the accuracy and reliability of the WDR simulation approach by comparing with the measurements. Meanwhile, the advantages and disadvantages of the three different models are compared for WDR simulation. Secondly, CFD simulations of WDR for the buildings of six kinds of typical shapes in the semi-empirical model of ISO 2009 were conducted. The improvements of the models are presented by comparing the simulation results with the prediction results of the semi-empirical model of ISO. And WDR field for the buildings of protruding facades that were not mentioned in the semi-empirical model was performed in consideration of the influence of protruding facade on the WDR quantity. Lastly, the distribution of WDR load of rain-wind-induced was simulated for different building shapes. The results show the WDR load is quite remarkable for some extreme weather.The conclusions in this paper can provide references for further research of WDR and design of engineering of different building shapes.