错列双钝体断面气动绕流干扰效应的数值模拟

Numerical Simulation of Aerodynamic Ambient Flow Interference Effect on Dual Bluff Body Section in Staggered Arrangement

为研究既有桥梁对近桥位复线桥的气动干扰,选取不同梁高典型断面,采用增强壁面处理(EWT)的数值模拟方法,对比研究了主梁断面高度、来流风攻角及风向等因素对错列双钝体断面间的气动特性影响,并对其流场结构进行了分析。研究结果表明:受既有桥梁影响,复线桥主梁断面在位于迎风向和背风向时,三分力系数与单幅断面差异显著。对于不同梁高情况,复线桥监测断面位于背风向时,迎风侧腹板负压区随遮挡面积的增大而增大,扭转效应更为明显,升力方向随梁高变化发生改变;对于不同来流攻角情况,背风向监测断面在负攻角下所受阻力较对应正攻角略大,攻角增大引起了断面间大涡的破裂。断面形状、高度、遮挡面积及来流攻角均在不同程度上引起绕流特性的改变。

In order to investigate the aerodynamic interference from existing bridge to nearby double-line bridge, by selecting typical sections at different beam heights and using EWT numerical simulation, the influence of the height of main beam section, wind attack angle and wind direction on the aerodynamic performance between sections of dual bluff body in staggered arrangement are compared, and the flow field structure is analysed. The results show that （ 1 ） by the influence of nearby existing bridge, aerodynamic coefficients of the main beam deck section of double-line bridge for windward side and leeward side are significantly different to those of the single deck section ; （2） for different beam heights, when the monitoring section is located on leeward side, the range of negative pressure zone on windward side web increases with the increase of ＂shielded area＂, the torque is more obvious and the direction of lift force changes with beam depth; （3） for different wind attack angles, the drag force on the monitoring section on slightly larger under negative wind attack angle than that under positive wind attack angle, between sections breaks down due to increasing of wind attack angle; （4） changes in ＂shielded area＂ and wind attack angle will cause different characteristics of ambient flow in leeward side is and large eddy shape, height, some extent.