H形断面的压力分布特性对其颤振性能的影响

Characteristics of pressure distribution on H-shaped section and its influence on the flutter performance

文中推导了采用模型表面压力来描述的颤振导数表达式,结合计算流体动力学方法,获取模型表面压力,分析颤振导数表达式中压力幅值和相位差的提取方法,研究模型表面压力分布特性对颤振导数以及颤振稳定性的影响。通过对模型进行合理分区,探讨模型表面不同区域对颤振导数的贡献,以此为基础分析了中央稳定板的抑振原理。研究结果表明,H形主梁上下表面旋涡的非对称分布造成了模型表面平均压力分布的非对称性,并使得模型产生顺时针转动力矩。当风速低于颤振临界风速时,对颤振导数A_2~*影响较大的分布压力会使模型产生逆时针转动力矩,从而维持了振动系统的平衡;而当风速达到颤振临界风速时,影响A_2~*的分布压力将会使模型产生顺时针转动力矩,因此破坏了振动系统的稳定性。

The expressions of flutter derivative described by the surface pressure of model were derived in this work. In combination with the computational fluid dynamics （CFD） , the surface pressure of model was achieved, the calculation method of pressure amplitude and phase difference in the expression of flutter derivative was analyzed, and the influences of surface pressure distribution characteristics on flutter derivatives and flutter stability were studied. By reasonably zoning the model, the contributions of different zones to the flutter derivatives were discussed, and furthermore, the vibration suppression principle of the central stabilized plate was analyzed. The research results show that the asymmetric distribution of vortexes on the upper and lower surfaces of girder with H-shaped section leads to the asymmetric distribution of the mean pressure on the model surface and the clockwise torque on the model. When the wind speed is lower than the critical wind speed of flutter, the pressure greatly affecting the flutter derivative A2＊ may lead to the counterclockwise torque on the model, so as to maintain the balance of the vibration system. When the critical wind speed of flutter is reached, the distribution pressure affecting the flutter derivative A2＊ may lead to the clockwise torque, which undermines the stability of system.