Two-dimensional Numerical Simulation On The Aerodynamic Performance Of The Hangers Of The Arch Bridge

The wind load can cause important influence on bridge structure’s safety andstability. The vortex-induced vibration is one of the most common phenomenon in thedynamic effects on the bridge. It may cause fatigue damage to the bridge and causesome impact on the traffic safety. Nowadays the development direction of modernarchitecture trends to longer, thinner, softer and lower damping, so we should studythe vortex-induced vibration of structure.The Nanjing Dashengguan Yangtze River suspension bridge is of the longesthangers more than50meters, the hangers are flexible and the vortex-inducedvibration of the hangers would easily occur in the slender hanger. The main work inthis paper is to use computational fluid dynamics software FLUENT to study theaerodynamic performance of the hanger of the bridge by numerical simulation, so asto provide the basis for the further study of the vortex-induced vibration. The liftcoefficient, drag coefficient and graph of the vortex shedding are studied andanalyzed in this paper. Then the optimal cross-section can be selected among therectangular, corner rectangular and round corner rectangular section, so as to restrictthe effects of wind-induced vibration.On the basis of the above work and taking the actual situation into account, wefurther study on the single and double corner rectangular cross-section hangers in thedifferent kinds of wind angle of attack, we compare and analyze the results ofnumerical simulation of the two case, then find the most unfavorable wind angle ofattack and the value of the angle of attack at which the two hangers have no mutualinterference. In this paper, the following conclusions are obtained:(1) With the wind speed increament, the Strouhal number corresponding to eachsection of the hanger is approximately constant.(2) With the wind speed increament, the lift and the drag corresponding to eachsection of the hanger is constantly increasing.(3) With the change of the shape of the hanger section from rectangle tochamfered rectangle, and to rounded rectangle, the wind speed that leads vortex-induced vibration is constantly decreasing.(4) At the same wind speed, with the change of the shape of the hanger sectionfrom rectangle to chamfered rectangle, and to rounded rectangle, the lift coefficient,lift, drag coefficient and drag is constantly decreasing.(5) Taking the wind angle of attack into account, we further study the hangerwith corner rectangular cross-section shape and find the most harmful wind angle ofattack occurs at20°~25°.(6) When further study the double hangers with corner rectangular cross-sectionshape and take the wind angle of attack into account, we find when the value of theangle of attack at15°, the two hangers have no mutual interference.