具有类似于圆形断面的细长结构常发生大幅的风致不稳定振动，气动力分析是研究该类振动机理的主要方法，雷诺数是该类结构气动力的主要影响因素之一。通过长短轴之比为1．5的椭圆形断面刚性模型测压风洞试验，得到了雷诺数从32 k～250 k范围内的气动力。讨论了雷诺数对平均气动力、平均风压分布、流动特征点、斯托洛哈数的影响规律。采用考虑雷诺数和振动方向影响的驰振稳定性分析方法，分析了该断面的驰振稳定性。结果表明，在高雷诺数范围内，随着雷诺数的增大平均阻力系数减小、平均升力系数随风向角的变化更剧烈、最小风压点和分离点向尾流移动、规则的漩涡脱落消失；在雷诺数对气动力有明显影响的区域内，气动阻尼为负值，结构可能发生驰振，横风向振动负气动阻尼主要归因于雷诺数对平均气动升力随风向角的变化的影响，顺风向振动负气动阻尼主要是由于平均气动阻力随雷诺数增大而减小造成的。%Wind induced large‐amplitude instable vibration occurs on slender cylinder with non‐edged cross‐section such as circu‐lar cylinder .Studies on aerodynamics force on the cylinder have significant contribution to solve prevent the vibration .The Reynolds number is an influencing parameter to determine the aerodynamic force on the cylinder .The rigid model pressure tests in wind tunnel are carried out to obtain the aerodynamic force on cylinder model with elliptical cross‐section that ratio of long axis to short axis is 1 .5 .Effects of the Reynolds number on mean aerodynamic force coefficients ,mean wind pressure dis‐tribution ,flow characteristic points and the Strouhal number are discussed .Considering the effects of Reynolds number and vi‐bration direction ,galloping instability is analyzed .The results show ,with increasing Reynolds number ,mean drag coefficients decrease ,variation of mean lift coefficient with the angle of attack become violent ,the minimal wind pressure points and sepa‐ration points move to leeward ,the regular vortex shedding disappear ;The aerodynamic damping is negative and galloping may happen at the range that the Reynolds number have significant effect on aerodynamic force .The negative aerodynamic damping at cross‐wind vibration mainly attribute to the effect of the Reynolds number on variation of mean lift coefficient with the angle of attack ;the negative aerodynamic damping at along -wind vibration is due to the drag coefficients decrease with an increasing Reynolds number .
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