定常吸气改善桥梁断面风致静力特性的数值

Numerical Investigation in Improving Aerodynamic Performances of Drag Force of Cross Section for Bridge Box Girders by Steady Air-Suction

目的改善桥梁断面空气动力特性,提高桥梁抗风能力.方法以某桥梁闭口扁平箱梁断面模型为研究对象,利用基于计算流体动力学的数值方法模拟来流风作用下桥梁断面的绕流风场,并计算桥梁断面静力3分力(阻力、升力、扭矩).结果静力计算结果显示,与未采用吸气情况下相比,定常吸气后断面的升力与扭矩基本没有变化,而阻力却显著降低,且随着吸气能量的增加吸气减阻效果加大.结论定常吸气可以有效地抑制风流过钝体断面而产生的分离,使主流更加贴近壁面,进而达到减少断面阻力的目的,定常吸气是桥梁断面减阻的有效手段.

The aerodynamic characteristics of bridge section with steady air-suction on the bridge deck undersurface closer to wind inflow have been investigated by numericallg simulating the wind flow field around cross section model of bridge box girders based on computational fluid dynamics. The results show that the lift-forces and the torsion-forces are almost not influenced and the drag-forces are decreased compared with the non-suction means. The drag-forces are decreasing with more and more steady suction energy. The air suction energy should be increased with more wind flow energy in order to keep the same decreasing amounts of drag-forces. The research results indicate that the steady suction is effective to reduce drag-force by restraining wind flow separation around blunt body and pressing the flow close to the section wall surface.