Numerical Simulation Of The Wind-Induced Building Skin Friction

Because of the influence of viscous fluid, skin friction can be caused on building surface by wind when it sweeps parallelly over the surface. For large-span roof, skin friction will go up with the roof area becoming larger. So, in some situations, we should take the friction into consideration. There are descriptions about skin friction caused by wind in EU regulations. But about the regulations of skin friction coefficient, there isn’t much introduction except three coefficients corresponding to three different surfaces which diverse in roughness. Similarly, in Chinese regulations of wind load, there aren’t much details about skin frictions caused by wind recently except some regulations of wind pressure. So, ignore the influence of skin friction in the structural design, may lead to unfavorable consequence under certain extreme conditions. Recent years, it happens occasionally at home and abroad that many Large-span roofs are damaged by wind disaster, because Large-span roofs are usually in an environment of low atmospheric boundary layer and intense turbulence. A systematic and in-depth study on skin friction coefficient has important theoretical significance and Engineering practical value. This article does numerical modeling on skin friction coefficient of large-span roof and studies the distribution of skin friction coefficient, providing references for structural wind-resistance design.In order to reasonably simulate skin friction coefficient, this article firstly generalizes the boundary layer theory and the simulating ways of wind friction. Referring to Murakami’s experiment of wind tunnel in1990, we simulate the fluid motion around cubic constructions, using the two-layer model and the standard k—ε model and discuss the parameter of the domain, meshing, boundary condition by numerical wind tunnel methods. Then this article continues to discuss the applicability of the two models to the numerical simulation method, especially the accuracy of the simulation near the wall.This article, with the help of ANSYS-FLUENT13.0, numerically simulates, using two-layer model, the friction of Large-span roof. Further more, it also studies and discusses skin friction coefficient according to specific roof forms. Based on sample flat-roof, this article analyzes the influence on the distribution of skin friction coefficient, considering the different distance of the rib, the wind direction and the different terrain roughness. Lastly, this article summarizes the distribute law of the skin friction coefficient, supplying references for engineering design.