流体横掠波状圆柱的动特性研究

Experimental Investigation to Dynamics of Wavy Cylinders in Cross Flow

提出了一种可减小流体诱导振动的波状圆柱,并对3种不同表面倾斜度的波状圆柱进行了实验研究.实验在一低速风洞进行,工作段的横截面尺寸为0.6 m×0.6 m,湍流度小于0.2%,雷诺数在2.0×104到5.0×104范围内.实验结果表明:波状圆柱与普通圆柱相比其脉动升力系数较小,具有减小流体诱导振动的作用;流体绕波状圆柱流动的斯德鲁哈尔数等于绕普通圆柱流动的斯德鲁哈尔数,说明波状圆柱的减振并不是通过改变其斯德鲁哈尔周期来实现的.

The effects of different degrees of obliqueness of wavy cylinders on flow-induced vibration suppression on cylindrical structures were experimentally investigated. The experiments were carried out in a low speed wind tunnel with 0. 6 m×0.6 m cross-section and free-stream turbulent intensity less than 0. 2%. The Reynolds numbers, based on the free-stream velocity and the nominal cylinder diameter, varied within 2.0 × 10^4 to 5.0 × 10^4. The measurements of fluctuating forces and Strouhal numbers induced by a cross flow over three kinds of wavy cylinders were implemented. It is concluded that the root-mean-square （RMS） fluctuating lift coefficients of the wavycylinders are much lower than those of right cylinders, which means a good effect of wavy cylinder on the suppression of flow-induced vibration. The spectral analysis of both hot-wire and load cell signals indicates that the Strouhal numbers of the wavy cylinders are naturally identical with ones of the corresponding circular cylinder, thus the vibration suppression capacity of wavy cylindrical structures is not resulted from the variation of Strouhal number.