Numerical Simulation Study On Aerostatic Coefficient Of Curve Continuous RigidFrame Bridge With High-pier And Long-span

In recent years,the flourishing development of science and technology and transportation in China is obvious to all,High piers and large span continuous rigid frame bridges have also been widely used,and gradually developed toward large spans,soft,ultra-high piers,and structural irregularities.The wind-resistant performance of a bridge is an important indicator for bridge design and application.In China’s " Wind-resistant Design Code for Highway Bridges",the aerostatic coefficient is only described for straight single bridge decks.At the same time,there is less research on wind resistance of curved continuous rigid frame bridges in China.Therefore,this paper combines the actual case of the Gulongshan Bridge and the CFD method to do research on the influence of the aerostatic coefficient of the curved box girder.Many times,high-performance computer clusters and parallel computing are effective solutions to reduce the time cost of numerical simulation.Therefore,this paper is also based on the high performance computing cluster of Hunan provincial Key Laboratory of Engineering Rheology and FLUENT software to carry out parallel computing research on the bridge wind field.lt also discusses the influence of factors such as the number of grids and the number of cores on the parallel efficiency and speedup ratio in the massive parallel computation of bridge wind farms,and the best matching relationship between grid number and core number.Specifically,the following aspects of the work are included:(1)This paper introduces the development of high-rise piers and large-span curved rigid-frame bridges in China,and summarizes the achievements of computational fluid dynamics(CFD)methods in bridge wind field research.(2)Based on the Linux version of FLUENT software,the extraction of the aerostatic coefficient of the box girder section of the Shandian Bridge was used as a numerical simulation verification scheme.The calculation results were in good agreement with the experimental data of the reference literature.(3)For the case study of the Gulongshan Bridge in this paper,a two-dimensional numerical simulation study of the aerostatic coefficient and flow field in the box girder section was conducted.The influence of aerostatic coefficient and flow field on wind speed,wind angle of attack,beam and other factors of the box girder section was discussed.The calculation results show that the influence of wind speed on lift coefficient is more obvious,especially as the wind speed increases,the lift coefficient increases.The drag coefficient and moment coefficient change little with wind speed.The influence of wind angle of attack on the lift coefficient is obvious.When the wind speed is 10m/s,the maximum lift coefficient is at the 0 degree angle of attack and decreases to both sides of the positive and negative angle of attack.The change of attack angle has little effect on drag coefficient and moment coefficient.With the increase of box girder height,the flow field becomes more complex and the details are more abundant.(4)This paper establishes a three-dimensional numerical simulation model for box girders of the Gulongshan Bridge.The influence of the aerostatic coefficient with the change of wind speed in a three-dimensional case of a straight box girder and the influence of the aerostatic coefficient and the flow field on the curvature of the box girder under a three-dimensional condition are studied.The calculation results show that the drag coefficient decreases slowly with the increase of radius of curvature,the lift coefficient and torque coefficient increase slowly with the increase of radius of curvature,and the value of aerodynamic coefficient changes little in general.(5)Based on the engineering rheology key laboratory of Hunan Province DELL computer cluster and FLUENT platform,established a three-dimensional numerical simulation system of bridge wind field under LINUX environment The study investigated the influence of factors such as the number of grids and the number of cores on the parallel efficiency and the speedup ratio in the massive parallel computation of the bridge wind farm,and the best matching relationship between the number of grids and the number of cores.The computation results show that the time consumed by computation increases with the increase of the number of grids,which is basically linear.In a certain number of cores,with the increase of the number of cores,the time consumed is greatly reduced,and when the number of cores exceeds a certain range,the decrease of the time consumed by the calculation is not obvious with the increase of the number of cores.In the numerical simulation of this paper,the best cores number range is between 2-6.