| As being characterized by long-span, lightweight and flexibility, cantilevered roofs are highly susceptible to the wind action. Because the characteristics of flow around structure are very complicated and the wind pressure distribution is significantly influenced by signature turbulence which induced by the structure itself, quasi-steady hypothesis is not applicable. Up to now, no appropriate wind load model can be used in design. So it is necessary to study the characteristics of wind load on the cantilevered roofs systematically and deeply to create the applicable wind load model. In addition, due to the sensitity to wind, local damages on the roof are easy to happen under strong wind. Therefore, it is valuable to make some research on aerodynamic control measures of this structure.Based on the above, studies on the characteristics of wind load are carried out systematically by CFD numerical simulation and wind tunnel test. Then the load models of mean wind and fluctuating wind are proposed. At last the method and mechanism of aerodynamic control are investigated deeply by CFD technique. The main research contents and results are presented as follow:1.According to the characteristics of structural wind engineering, the key problems on CFD techniques applied in simulating mean and fluctuating wind load are investigated.(a) The problems on determining computational region, selecting turbulent model and dividing grid are investigated to provide reference for engineering.(b) Because there are some difficulties when LES is used in building field, a series of efficient techniques are adopted to resolve the problem on how the LES is used under inflow boundary condition of turbulence. And the validity is proved by numerical example. The main techniques and conclusion are as follow:â‘ An improved simulation method called WAWS/POD is brought forward, which combines weighted amplitude wave superposition (WAWS) and proper orthogonal decomposition (POD) technique. The computational efficiency, in both time and memory consumption, of simulating fluctuating velocity by using the combined method is improved obviously with negligible loss of accuracy, which is effective to solve the overrunning problem of matrix dimension in simulating random process with multiple-points and long time series;â‘¡The time series of wind velocity generated by the WAWS/POD method do not satisfy the continuity equation, which reduces the convergence of LES. In the article, free-operation of divergence is used to resolve the convergence problem which improves the computational efficiency on simulation of unsteady flow;â‘¢LES numerical simulation costs computer resource greatly. In order to improve the computational efficiency, the UDF interface routine using parallel computation is worked out based on the FLUENT software platform.2.The influence of mean wind load on the cantilevered roofs due to some factors such as the incoming flow condition, inclination angle of roof, span-height ratio, the ventilation rate in stand's behind, the type of stand and interfere induced by upstream stand is studied by using CFD numerical simulation. Based on the research above, the mean wind load model is set up.3.The characteristics of fluctuating wind load is investigated by using LES numerical simulation and wind tunnel test. Then the fluctuating wind load model is build up.4.The method and mechanism of aerodynamic control applied on bluff body are investigated. Two kinds of aerodynamic control equipments are designed to improve the flow characteristics around the cantilevered roofs and their feasibilities are verified.
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