Study On Wind-Induced Mean Internal Pressure Of Long-Span Roof Building With Opening By Numerical Simulation

Buildings with long-span roofs appear in China commonly in recent years since this kind of buildings is with beautiful external appearance and can be well used, but this kind of buildings is very sensitive to wind loads, it is of great practical value to study the wind-induced influence caused by openings on difference parts of a building with long-span roof, while openings are on the cantilevered parts of the roof, it is favorable for the roof, and wind-induced internal pressures are caused while openings are on others parts of the building.Computational Fluid Dynamics (CFD) is a new subject originated from about 40 years ago, which is having been had regard for and been applied in lots of regions in over 10 years. Compared with the traditional methods of structure wind engineering, CFD has obvious predominance, yet which has many problems in practice because of its imperfectness. The basic theory of CFD is introduced in this paper: The general discrete equation can be derived from the general form of the governing equations on the computational mesh, and then numerical methods of flow fields are showed, therefore simulation methods of the turbulent flow are classified, finally near-wall treatments in the turbulence simulation are introduced.A typical long-span roof building with a long cantilevered length is modeled and computed by CFD method, comparisons between the results from the wind tunnel test and the numerical simulation are then performed to know the accuracy of the simulation, then respective numerical simulation studies on the two practical wind loads mitigation measures of carving holes in the cantilevered part of the roof and adding a parapet around the edge of the roof are carried out, therefore the respective wind loads mitigation effectiveness are understood, hence this article can be give reference to practical wind loads mitigation projects.After that, another long-span roof structure without and with one opening in the windward face are modeled and computed, and results from the wind tunnel tests and the numerical simulations are compared, then the theoretical formula for estimatingthe wind-induce mean internal pressure is derived from Bernoulli equation, and then several cases whose openings have different positions, areas and numerical measures are simulated to roundly analyze the applicability of the numerical simulation on computing wind-induced mean internal pressure, also theoretical estimating means in complex opening conditions is discussed, finally a recommendatory method to determine wind-induced mean internal pressure in practical works is provided.