The Reaserch Of Wind-driven Rain Amount And Its Pressure On Building Envelopes Based On CFD Numerical Simulations

China is one of the country tropical cyclone visits most frequently in the world. Each landing of typhoon will cause vast structure damage and casualties, and thus cause huge losses to the national economy. The intensive rainfall is always accompanied with typhoon and impacts building envelops, which intensified the damage of structures as the striking of massive raindrops. Therefore, how to comprehensively grasp the wind-driven rain (WDR) amounts and its pressure distribution characteristics on the extensive mid and high-rise building’s windward is highly necessary for the WDR load design, and moreover, to find out the corresponding WDR resistance ways.In this paper, the CFD numerical simulation method is applied to rsearch the wind-driven rain amount and rain pressure distribution characteristics on the mid and high-rise building’s facades. The averaged Navier-Stokes equation and the Realizable k-ε turbulent model were established, and then introduced the Euler-Euler multiphase flow model, moreover, the building facades were special treated by using User Defined Function, combined with the raindrop spectrum and raindrop terminal velocity formula, to solve the volume fraction of raindrop and raindrop velocity, finally, the information of WDR fluid field was obtained.First of all, the raindrop trajectory, WDR rain amount and rain pressure were obtained under different wind velocity and rain intensity by the solution of mid and high-rise building WDR fluid field. The result show that with the increasment of wind velocity and rain intensity, the WDR catch ratio and its pressure on the windwards were amplified in different degrees, their distribution regularities presented to be increased from bottom to top and center to sides. What’s more, the maximum parameter occurred at top-sides, and the maximum WDR load at mid and high-rise building’s windward envelopes can account for6.86%and7.10%of pure wind load, respectively.Next, the article simulated the impacts of different distribution of buildings to the WDR moving and distribution characteristics. The result indicated that the WDR catch ratio and its load distribution on the windward of front buildings were similar to the single building’s, while the rear building’s windward have changed a lot, and moreover, from which the article obtained the WDR distribution law caused by the changing of space and rank between buildings. Clearly to see, the closer the distance to be, the stronger the disturbance to be turned out, thus the Prain/Pwind was diminished on the windward envelopes of both mid and high-rise buildings, especially on the mid height building’s. When the arrangement staggered, the WDR distribution changed most obviously, particularly, the WDR catch ratio and its load all increased distinctly on the windward of rear mid-rise building.The research results of the article can provide reference and guidance for the WDR research and weather-resistance design of super high-rise buildings and complex group buildings.