Predictions and Model Tests of an SCR Undergoing VIV in Flow at Oblique Angles
Predictions and Model Tests of an SCR Undergoing VIV in Flow at Oblique Angles
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DOI：
10.1115/omae2004-51563
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发表时间：
2004
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影响因子：
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通讯作者：
G. Moe;T. Teigen;P. Simantiras;N. Willis;H. Lie
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文献类型：
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作者：
G. Moe;T. Teigen;P. Simantiras;N. Willis;H. Lie
本文描述了现有的计算机代码VICoMo（见Moe & Arntsen(2002)）如何扩展到分析流既不在立管平面内也不垂直于立管平面的SCR的涡激振动（VIV）。为了使解决方案能够处理倾斜角度的流动，尝试了各种策略。研究发现，最好的方法是假设立管运动发生在与流动垂直的平面上，而忽略流动方向的运动。不确定性的一个来源与VICoMo中的经验数据库有关，该数据库基于流体垂直于立管元件的测试。实验的时间序列显示出很大的时间变化。实际上，在给定点的平均运动幅度可能是最大值的低一半。此外，在立管上的实验包线上不同点的最大振幅通常是在完全不同的时间达到的。这些特征不包括在理论模型中，使得预测和测量之间的直接比较变得困难。我们最后比较了运动响应的包络。在一些情况下，预测结果在频率、模态和振幅方面与实验结果非常吻合。然而，在其他情况下，这种匹配就不那么令人满意了。ASME版权所有©2004
The paper describes how an existing computer code, VICoMo, see Moe & Arntsen (2002), has been extended to analyse Vortex Induced Vibrations (VIV) of SCR’s for situations in which the flow is neither in the plane of the riser, nor perpendicular to it. Various strategies were attempted in order to make the solution deal with flows at oblique angles. It was found that the best approach was to assume that the riser motions occurred in plane perpendicular to the flow, while motions in the flow direction were disregarded. One source of uncertainty is associated with the empirical database in VICoMo which is based on tests in which the flow was perpendicular to the riser elements. The timeseries from the experiment showed large temporal variations. Actually the average motions amplitudes at given points may be as low half of the maximum value. Also the largest amplitudes at different points on the experimental envelope on the riser will usually have been reached at quite different times. These features were not included in the theoretical model, and made direct comparisons between predictions and measurements difficult. We ended up comparing the envelopes of motion response. In several of the cases the predictions matched the experiments closely, for frequency, modeshape as well as amplitudes. In other cases the match was somewhat less satisfactory, however.Copyright © 2004 by ASME