| The cantilevered roof of Fujian circular Tulou building is a wind-sentitive structure due to its overhang eaves and fragile construction materials,which in the multiple typhoons of our country.In order to improve its wind disaster prevention level and ensure its wind safety,the CFD numerical simulation method is used to study the wind load distribution characteristics of the roof surface.Aerodynamic windproof measures to enhance its windproof performance are proposed.The results can provide reference for the wind resistance design of this type of structure,including:(1)The feasibility of the numerical simulation method is verified.By comparing wind pressure distribution of cantilevered roof of circular Tulou of the numerical simulation results with the wind tunnel test,verify the feasibility of the selected Realizablek-εturbulence model and FLUENT software related parameter setting.(2)The wind load distribution characteristics of cantilevered roof of circular Tulou are studied.The results show that:under 0°wind direction,the wind pressure coefficient of cantilevered roof is basically distributed symmetrical along the center line of 0°wind direction.The upper surface of cantilevered roof is dominated by negative pressure,while the windward side is larger.The windward side of inner and outer cantilevered roof has the largest absolute value of wind pressure coefficient,which is the wind-sensitive structure.(3)The effects of different cantilever roof angle or length on wind load distribution characteristics on the upper and lower surfaces of cantilever roof and the wind pressure coefficient at the end of cantilever roof are studied.The results show that the wind load distribution of cantilever roof’s surface will not be changed by changing the slope angle or cantilever length.With the increase of slope angle of cantilever roof,the wind pressure at the cantilever end on the upper surface of cantilever roof changes obviously.The absolute value of the wind pressure coefficient of the inner cantilever roof increases,the absolute value of the maximum wind pressure coefficient of outer cantilever roof decreases,and the wind pressure on the lower surface of the cantilever roof has no obvious change.With the increase of cantilevered length,the wind pressure on the upper surface of cantilevered roof changes obviously.The absolute value of the wind pressure coefficient at the measuring point at the end of the inner cantilevered roof gradually decreases,while the absolute value of the wind pressure coefficient at the measuring point of the outer cantilevered roof increases,but the change of the wind pressure on the lower surface of the cantilevered roof is not obvious.(4)Considering the characteristics of cantilever roof,wind load distribution characteristics,engineering practicability,feasibility and other factors,three aerodynamic wind resistance measures are proposed to improve the wind resistance performance of cantilever roof,namely,adding vertical and corrugated wind shields at the end of the cantilever roof,adding vertical wind shields at the ridge of the cantilever roof.To explore the impact of different geometric sizes of windshields on their wind resistance performance,including the height of the windshields,the angle of the windshields and the radius of the circular arc of the corrugated windshields.The research shows that:after adding different windshields and optimizing their geometric dimensions,the circular Tulou cantilevered roof is unloaded the wind pressure coefficient to a certain extent.Among them,the corrugated windshields are added to the end of the outer cantilevered roof,the unloading effect is the best when the geometric dimensions are relative height h/H_j=0.05,inclinationθ=-45°,and radius of corrugated arc R=5.5m.The reason is that the slanted corrugated windscreen blocks the incoming flow on the surface of the cantilever roof,making the vortex formed by the impact of air flow transfer from the cantilever end of roof to the surface of the windscreen.At the same time,the existence of corrugations reduces the intensity of the airflow vortex on the surface of the inner and outer cantilever roof,so as to achieve the effect of unloading the wind load on the roof. |
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