Abstract: Parallel cables with close range were used extensively in practical engineering. However, there were limited studies on the aerodynamics of parallel cables as well as their Reynolds number effects, especially at critical Reynolds regime. When Reynolds numbers were between 0.9×105~3.2×105, located in subcritical Reynolds regime and critical Reynolds regime, the aerodynamic characteristics of twin circular cylinders with close range along with their Reynolds numbers effect were investigated through a series of wind tunnel tests. Results show that the aerodynamic forces of two circular cylinders with close range have strong Reynolds number effect; with different wind attack angles, the average aerodynamic coefficients of circular cylinders in the critical regime are very different from those in subcritical regime. In the critical Reynolds number region, the mean lift coefficient of the downstream cylinder can reach more than 1.35, and the mean lift coefficient and drag coefficient suffer a discontinuous change with the change of Reynolds number, which may relate to the shift of the flow state. The mean lift coefficient of the upstream cylinder can reach more than 1.0, and the mean lift coefficient suffers a discontinuous change with the change of the Reynolds number, which may relate to the shift of the flow state of flow around twin circular cylinders.

Key words: bridge engineering, cablesupported bridge, wind tunnel test, flow around circular cylinder, Reynolds number effect

摘要： 近距离并列索在工程实际中有着广泛的应用，但针对并列索的气动性能及其雷诺数效应的研究并不多，特别是在临界雷诺数区域。通过风洞试验，在雷诺数Re=0.9×105~3.2×105之间（涉及亚临界雷诺数和临界雷诺数）研究了近距离双圆柱的气动性能及其雷诺数效应。研究结果表明：近距离双圆柱的气动性能有强烈的雷诺数效应，在不同的风攻向角下，临界雷诺数的圆柱平均气动力系数与亚临界区有很大差异；在临界雷诺数区域，下游圆柱的平均升力系数可达到1.35以上，平均升力系数与阻力系数会随雷诺数的变化发生不连续突变，这应该是流态发生了变化；上游圆柱的平均升力系数可达1.0以上，平均升力系数会随雷诺数的变化发生不连续突变，这种气动力的突变与双圆柱绕流场的流态结构的变化有关。

关键词: 桥梁工程, 缆索承重桥, 风洞试验, 圆柱绕流, 雷诺数效应