Effects of geometrical parameters on the aerodynamic characteristics of a streamlined flat box girder
Effects of geometrical parameters on the aerodynamic characteristics of a streamlined flat box girder
复制标题
几何参数对流线型扁箱梁气动特性的影响
DOI：
10.1016/j.jweia.2017.08.009
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发表时间：
2017-11-01
影响因子：
4.8
通讯作者：
Liu, Mengting
中科院分区：
文献类型：
--
作者：
He, Xuhui;Li, Huan;Liu, Mengting
通过风洞试验，系统研究了宽高比（B/D）、整流罩角（θ）和相对风鼻高度（H/ h，h和H分别为风鼻到主梁上下表面的距离）对流线型扁平箱梁气动特性的影响。在B/D = 6、9和12，θ = 45 °、55 °、65 °和75 °，H/h = 1、2、3和4的情况下，共进行了21个工况的试验，覆盖了大部分典型的在用大跨度桥梁。基于自由滑行迎面速度U-无穷大和模型高度D的雷诺数为3.3 x 10（4）。实验结果表明，在小攻角下，B/D、θ和H/h的影响可以忽略不计|阿尔法|与|阿尔法|< 4度。梁的气动性能对这些几何参数非常敏感，|阿尔法|< 4度，这与主梁周围的流动状态有关。随着|阿尔法|梁的绕流可以从后缘涡脱落（TEVS）转变为前缘冲击涡（ILEV）和前缘涡脱落（LEVS）。一般来说，H/h = 2-3，B/D和θ较大的主梁对应的TEVS α值范围较大，有利于主梁的抗风稳定。
The effects of aspect ratio (B/D, width to height ratio), wind fairing angle (theta) and relative height of wind nose (H/ h, h and H are the distances from the wind nose to the upper and lower surfaces of the girder, respectively) on the aerodynamic characteristics of a streamlined flat box girder were systematically investigated through wind tunnel experiments. A total of 21 cases were tested with B/D = 6, 9 and 12, theta = 45 degrees, 55 degrees, 65 degrees and 75 degrees, and H/h = 1, 2, 3 and 4, which covered most of the typical large span bridges in use. The Reynolds number based on the freestream oncoming velocity U-infinity and model height D was 3.3 x 10(4). The experimental results show that the effects of B/D, theta and H/h are negligible at small wind attack angle |alpha| with |alpha| < 4 degrees. The aerodynamic performance of the girder is very sensitive to these geometric parameters at |alpha| < 4 degrees, which is associated with the states of the flow around the girder. With the increases of |alpha| the flow around the girder may transfer from trailing edge vortex shedding (TEVS) to impinging leading edge vortex (ILEV) and leading edge vortex shedding (LEVS). Generally, the girder with H/h = 2-3 and larger B/D and theta corresponds to larger range of alpha with TEVS, which is favorable to the wind resistance stabilization of the girder.