Nymerical And Site Experimental Study For Wind And Rain Effects On Low-rise Buildings

China locates on the west bank of the Pacific Ocean, has a long coastline and monsoon climate. Over the years, the southeast coastal areas have been affected by the typhoon disaster frequently. The arrival of typhoon is always accompanied by storm. Effects of wind and rain is one of the most important reasons for destroy of low-rise buildings in coastal areas, which is a big threat to the safety of the building. Domestic and foreign studies on rain load of buildings are less so for. Therefore, the research on the effects of wind and rain on low-rise buildings is of great significance and also provides the theoretical and technical basis for wind resistance designs.In this paper, the numerical simulation technique based on CFD (Computational Fluid Dynamics) is first employed for study of the wind-driven-rain (WDR) effects on3-D (three-dimensional) low-rise buildings. In the study, the wind field under different wind speed is simulated so that the wind load distribution of the windward facade can be obtained. Then the discrete phase model (DPM) is employed to find the trajectories of the randomly inserted raindrops. The location, velocity and mass flow of each trajectory on windward facade can be determined. In the post-proceeding analysis, the windward wall is divided into several blocks. For each block, a statistical analysis is carried out to find the distribution characteristics of wind load, local intensity factor of WDR (LIF) and rain load on windward facade.On the basis of three-dimensional numerical simulation, the influence of different wind angles on WDR effect on the building is examined. Three types of wind angle:30°,45°and60°are considered, in which the analysis is emphasized on the case of200mm/h rainfall intensity. The distribution of wind load, local intensity factor of WDR (LIF) and rain load on windward facade along the horizontal direction and the vertical direction under different wind angle are found thereafter.Finally a site experimental study is carried out for a typical low-rise building. The main instruments, experiment scheme, experimental steps and the specific process are introduced. The site experimental results are compared with those of the numerical simulation. The above numerical and site experimental studies indicate that only under the extreme weather conditions with heavy wind (velocity larger than lOm/s) and heavy rain (intensity larger than100mm/h) arriving simultaneously, the resulting rain load is considerable. As for the weather conditions with wind velocity being10m/s-30m/s and rainfall intensity being100mm/h-200mm/h, the upper limit values of rain load would arrive at15%-25%of the corresponding wind load.