中文摘要：

方形断面是土木工程领域高层、高耸结构最常用的断面形状之一,横风向涡激共振是影响该类结构安全的重要因素。通过刚性节段模型测压试验,研究了方形断面结构气动力特性、旋涡脱落频率随风向角的变化规律,得到了该类结构发生涡激共振时的风速。研究结果表明：风向角影响其旋涡脱落频率,从而影响其涡激共振发生风速。当风向与方形断面迎风向夹角为74°左右时,方形断面发生横风向涡激共振的临界风速最低。

英文摘要：

Square cross-section is commonly used in high-rise structures in civil engineering. The vortex-induced vibration （VIV） is one of significant factors which threaten the safety of these structures. A rigid section square cylinder model is used in a series of pressure test in a wind tunnel to study the variation of aerodynamic forces and vortex shedding frequencies with the angle of attacks. The critical wind speed of VIV also is estimated. The results show that the angle of attack have a significant effect on aerodynamic forces and vortex shedding frequency on which the critical wind speed of VIV depends. As for the square cylinder, the lowest critical wind speed of VIV occurs when the angle between wind and the windward face of the model is around 74.