Abstract: In order to improve the aerodynamic performance of the standard square cylinder with sharp corners and straight edges, taking analogous square cylinder modified by the shape of angle (sharp angle, fillet) and edge (straight edge, concave edge and convex edge) as research objects, the aerodynamic performance and flow field characteristics of six kinds of two-dimensional cylinders with different wind direction angles were studied under low Reynolds number by using unsteady numerical simulation method. Research results show that the modification of the angle and edge shape of the standard square cylinder can obviously change the flow field structure and improve or degrade its aerodynamic performance. Compared with the straight edge cylinder, the aerodynamic coefficient and the wind pressure coefficient of the convex edge cylinder decrease obviously, while those of the concave edge cylinder intend to increase. Compared with the sharp corner cylinder, the aerodynamic coefficient of the rounded cylinder shows a trend to decrease in all wind direction angles, and the Strouhal number increases. On the whole, among the six types of cylinder studied, the aerodynamic performance of the convex edge cylinder with rounded corners is the best, and that of the concave edge cylinder with sharp corners is the worst.

Key words: bridge engineering, flow around square cylinder, numerical simulation, aerodynamic control, aerodynamic characteristic, flow field structure

摘要： 为了改进标准方柱(直边尖角柱)的气动性能，以经过角(尖角、圆角)、边(直边、凹边和凸边)形状修正的类方柱为研究对象，采用非定常数值模拟方法，在低雷诺数下研究了6类二维柱体在不同风向角下的气动性能和流场特性。研究结果表明：对标准方柱的角、边形状的修正可明显改变其绕流场结构，会改善或劣化其气动性能；与直边柱体相比，凸边柱体的气动力系数和风压系数明显减小，而凹边柱体的气动力系数和风压系数均有增大的趋势；与尖角柱体相比，圆角化后柱体的气动力系数在所有风向角下呈整体下降趋势，Strouhal数增大；从总体上看，在研究的6类柱体中，凸边圆角柱的气动性能最好，凹边尖角柱的气动性能最差。

关键词: 桥梁工程, 方柱绕流, 数值模拟, 气动控制, 气动性能, 流场结构