附属构件及桥面粗糙度对近流线型宽体箱梁气动静力系数的影响  

Effects of subsidiary members and deck surface roughness on the aerodynamic coefficients of static forces on a flat box girder

作　　者：张亮亮[1,2] 吴波[1,2] 杨阳[1,2] 刘连杰[1] 刘书洋[1] 

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]山地城镇建设安全与防灾协同创新中心,重庆400045

出　　处：《实验流体力学》2016年第1期74-80,共7页Journal of Experiments in Fluid Mechanics

基　　金：国家自然科学基金(51578098);重庆市科委项目(20130844)

摘　　要：针对高宽比为1/12的近流线型宽体箱梁进行了一系列参数化的三分力测力试验,研究了栏杆透风率、检修车轨道位置、桥面粗糙度对三分力系数的影响。运用CFD工程软件Fluent 15.0模拟二维风场,对三分力系数变化的可能机理进行讨论。结果表明,对于近流线型宽体箱梁:(1)随迎角由负到正加大,C_D先降后升,C_L与Cm总体趋于升高,但均不关于零迎角对称或反对称;(2)栏杆透风率的减小一方面加大了断面挡风面积,使尾流变宽,C_D升高;另一方面扩大了断面上方负压区范围(正迎角工况),提高了上表面压力系数(负迎角工况),使正、负迎角下的升力均增加,即C_L绝对值升高;(3)正迎角来流时,检修车轨道的内移使断面下方的负压区缩小、压力系数减小、尾流变窄,则C_D、C_L均降低;但负迎角来流时,其位置的移动未对分离区造成明显影响,则C_D与C_L均未出现显著波动;(4)正迎角来流时,桥面粗糙度的提高减小了上表面的分离角,使负压区缩小、尾流变窄,则C_D降低;且负压区的缩小使得朝上的升力减小,即C_L降低。负迎角来流时,粗糙度的提高使上表面的阻力与压力系数均增加,则C_D升高、C_L的绝对值升高;(5)栏杆透风率、检修车轨道位置及桥面粗糙度对Cm的影响可以忽略不计。Taking Cuntan Yangtze Bridge, which has a height-width ratio of 1/12, as an example, a series of parametric wind tunnel tests were conducted to study the effects of ventilation rate of railing, location of overhaul-dolly rails and deck surface-roughness on the bridge＇s aerodynamic coefficients of static forces. The possible variation mechanism of the aerodynamic coeffi- cients were also discussed via comparing the flow patterns and characteristics simulated by CFD software Fluent 15.0. The following results are obtained for a streamlined flat box girder： （1） As attack angle increases from negative to positive, the drag coefficient （CD） decreases firstly and then increases, while both the lift coefficient （CL） and moment coefficient （Cm） have an overall tendency of increasing. （2）The decrease of ventilation rate, on the one hand, results in an in- crease of the wind acting area, which leads to an expansion of the wake zone and a consequent increase of CD on the other hand, it extends the negative pressure zone in the case of positive attack angles, or increases the pressure coefficients on the upper surface in the case of negative attack angles, so that the magnitude of CL increases in both cases of positive and negative attack angles. （3） In the case of positive attack angles, when the overhaul-dolly rails are moved inward, the blunt degree of the cross section is reduced , narrowing both the negative pressure zone and the wake zone, and decreasing both CD and CL consequently. However, in the case of negative attack angles,the changes of separation and reattachment processes are not significant when the overhauldolly rails are moved, and therefore neither CD nor CL has a significant fluctuation. （4）In the case of positive attack angles, the increase of deck surface roughness narrows the separation zone over the upper face and the wake zone,leading to the decrease of both CD and CL. In the case of negative attack angles, the increase of the deck surface roughness leads to an increas

关 键 词：扁平箱梁 气动静力系数 节段模型试验 桥面粗糙度 栏杆透风率 检修车轨道位置 绕流场特性 

分 类 号：U441.2[建筑科学—桥梁与隧道工程]