Distribution of damping device on riser pipe in sheared currents
Distribution of damping device on riser pipe in sheared currents
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DOI：
10.1016/j.oceaneng.2015.05.028
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发表时间：
2015-08
影响因子：
5
通讯作者：
Y. Nishi;Phan Viet Doan
中科院分区：
文献类型：
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作者：
Y. Nishi;Phan Viet Doan
本文利用梁振动的数学模型和数值计算，研究了一种抑制立管涡激振动的方法。该方法使用部分覆盖立管的减振装置，使得测量阻力分布与特征函数平方重叠的积分最大化。通过考虑折合速度等值线和升力大小系数的垂直分布，我们确定了在不使用阻尼器的情况下最显著增长的模式。我们认为这种模式应该是一种应该被强烈阻尼的模式，从而根据重叠积分的近似最大化来配置一个附加的阻尼分布函数。我们将这种方法应用于线性剪切流中的立管，发现适当的阻尼模可以抑制VIV的程度与整个覆盖范围相同，尽管这种影响随流速剪切的强度而不同。结果表明，该方法对安装少量减振装置的涡激振动具有较好的抑制效果。
This study investigates a method for suppressing the vortex-induced vibration (VIV) of a riser pipe using a mathematical model of beam vibration and numerical computation. The proposed method uses damping devices that partially cover the riser pipe such that the integral measuring the overlap of the drag distribution with the eigenfunction squared is maximized. By considering the isolines of reduced velocity and vertical profiles of magnitude factor of lift force, we specified a mode that would grow most prominently if no damping device is used. We regard this mode as the one that ought to be intensively damped, thereby configuring an added damping distribution function according to the approximate maximization of the overlap integral. We applied this method to a riser pipe in linearly sheared flows and found that the appropriate specification of the damped mode can suppress the VIV to the same degree as the entire coverage, although this effect varies with the strength of the flow velocity shear. It follows that the proposed method is useful for suppressing the VIV with a small number of damping devices attached.