Numerical Simulation Of Wind Load During Opening Of Flat Roof Corner Of Low Rise Building

According to the wind disaster investigation,the damage of low buildings is the main cause of casualties and property losses in the wind disaster.The research on the wind load when low-rise buildings are damaged is conducive to study the damage law,find the weak link of wind resistance of low-rise buildings,study the wind pressure distribution characteristics after roof damage,prevent secondary damage,and provide reference for the wind resistance design and reinforcement of low-rise buildings.This paper summarizes the research status of CFD method and numerical simulation of low wind load at home and abroad.This paper introduces the basic theory of wind engineering and the basic governing equations of computational fluid dynamics.The standard model of Texas University of Technology(TTU)is numerically simulated and verified by FLUENT software platform.The effectiveness of six main turbulence models on the wind load of low buildings is compared.By comparing with the field measurement of TTU standard model and the test data of Tongji University building wind tunnel(TJ-2),the Realizable 6)- is finally selected The model is used to study the numerical simulation of low buildings.Through the numerical calculation of several different CFD simulation parameters,it is found that the first-order upwind scheme is Realizable 6)-The simulation results of the model for the roof negative pressure area are in good agreement,while the wall function and outlet conditions have little influence on the accuracy of the numerical simulation results.This paper focuses on the numerical simulation of the opening process of the roof corner of the low rise building with flat roof.The CFD transient simulation is used to calculate the wind load distribution characteristics of the flat roof corner of the low rise building from closure to opening.The transient peak effect of the transient opening on the indoor wind pressure is considered,and the wind pressure time history analysis and fluctuating internal pressure power spectral density during the transient failure are studied,The relationship between the peak value of transient internal pressure and vortex separation frequency and Helmholtz frequency caused by opening is analyzed.Finally,this paper studies the influence of factors such as the increase of opening rate and the change of opening shape on the distribution of wind pressure on the building roof.Through the analysis of indoor and outdoor synthetic pressure on the building roof and the edge of the opening,this paper studies the variation law of wind pressure on the roof caused by the further development of the opening after the transient failure of the building.The research shows that CFD technology can effectively simulate the wind load distribution of low buildings,and the simulation results are in good agreement with the field measurement and wind tunnel test results.Through the numerical simulation of 89 working conditions,it is found that the peak overshoot effect of building internal pressure will be caused at the moment of roof break.When the roof opening is in the windward position,the dangerous point of roof wind load composite pressure is located at the edge of the opening.The increase of roof opening rate and windward scale of the opening will also increase the wind load composite pressure on the edge of the opening.