Effect Of Groove On Wind Load Characteristics Of Long Span Cantilevered Roof Structure

With the development of economy and the progress of society,the large span space structure is more and more serving people’s life.The cantilever roofs with large span spatial structures have strong wind sen sitivity,and the wind resistant design is always a difficult problem in the structural design process.The groove is common used in the cantilevered roof,groove type and size,has a great influence on the local pressure cantilevered roof.In this paper,the computational fluid dynamics(CFD)method is used to study the influence of groove on the wind load characteristics of long-span cantilevered roofs.The influence of groove type and shape parameter on the wind pressure distribution mechanism of roof is investigated,and the zonal shape coefficient of groove roof is obtained;Considering the geometric parameters of large span cantilevered roof model and the influence of environmental parameters,the shape coefficient is modified to provide reference for engineering practice and related scientific research.The main contents include:By analyzing the vortex shape of different types of groove roof,the wind pressure distribution mechanism of the groove roof is studied.The results show that,in the leading edge of the roof,the setting of the groove made the vortex center of the score off the vortex closer to the roof,and the disturbance of the vortex on the roof wind pressure is strengthened.In the rear area of the roof,the reattachment of the vortex effectively hinders the generation of the secondary vortices,and the disturbance of the vortices on the roof wind pressure is weakened.The vortex characteristics at the top and bottom of the groove are different,and the vortex generated at the top is more intensive and has a wider range of action.Two typical grooves(corrugation and sawtooth)are chosen to study the influence of groove form and geometric parameters on the wind load characteristics of roof.The research shows that,compared with the flat ro of,the overall wind pressure coefficient of the corrugated groove roof increased by nearly 13%.and increased by 18% in the leading edge of the roof.The overall wind pressure coefficient of the sawtooth groove roof increased by 11%,and increased by more than 20% in the leading edge of the roof,and the maximum reached 40%(the middle zone of the roof leading edge).The geometric parameter analysis shows that the shape parameter has little influence on the overall wind pressure coefficient of the roof sur face;For the wind pressure coefficient of the local area,the variation of the sawtooth angle and the bottom width has great influence on the roof wind pressure,and the influence amplitude is close to 10%.Through the parametric analysis,the influence o f the coupling effect of 4 factors,such as roof inclination angle,ventilation rate,height span ratio and landform type,on the shape coefficient is studied.It is found that the inclination angle has the greatest influence on the roof shape coefficient,and has linear relationship in the specific area.According to the wind load characteristics of the groove roof,the aerodynamic optimization strategy of the roof wind pressure based on the opening is proposed and quantified,which can effectively reduce the overall wind pressure coefficient of the roof and the leading edge wind pressure coefficient.The effect of hole opening rate and opening position on roof wind pressure is quantitatively studied,which is convenient for engineering design.