OrcaFlex predictions for a multi-float hinged WEC with nonlinear mooring systems: Elastic mooring force and dynamic motion
OrcaFlex predictions for a multi-float hinged WEC with nonlinear mooring systems: Elastic mooring force and dynamic motion
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DOI：
10.1016/j.oceaneng.2023.115504
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发表时间：
2023-10
影响因子：
5
通讯作者：
Chenyu Zhao;P. Stansby;L. Johanning
中科院分区：
文献类型：
--
作者：
Chenyu Zhao;P. Stansby;L. Johanning
系泊系统可以影响WEC的运动和能量输出特性。本研究调查了SPM系泊系统在M4 6浮子WEC中的作用。通过Orcaflex和实验方法对M4的比例模型进行建模。与实验结果相比，数值计算结果的准确性对OrcaFlex中的模拟方法敏感，而滤波器方法与实验结果吻合较好。在选择数值方法后，引入另外两种系泊缆，比较不同刚度特性对张力折减的影响。与其他两个系泊缆相比，具有负弯曲的缆3在所有波浪条件下具有最低的张力峰值谱密度;然而，需要优化其刚度以降低某些大浪条件下的峰值张力。据此，缆绳3的刚度被初始调整，并且新缆绳3可以减少高达30%的偏移距离和50%的峰值张力。结果还发现，M4的相对旋转运动对刚度特性不敏感，这意味着未来PTO的选择可能与系泊缆无关。
The mooring system can affect the motion and energy output characteristics of a WEC. This study investigated the effects of an SPM mooring system in a M4 6-float WEC. The scaled model of M4 was modelled via both Orcaflex and experimental approaches. Compared with experimental results, the accuracy of the numerical results was found to be sensitive to the simulation methods in OrcaFlex, and the filter method supplied a better agreement with experimental results in this study. Following the numerical method selection, another two mooring cables were introduced to compare different stiffness properties with respect to tension reduction. Compared with the other two mooring cables, cable 3 with negative bending has the lowest peak spectral density of tension in all wave conditions; however, its stiffness needs to be optimised to reduce the peak tension in some large wave conditions. According to this, the stiffness of cable 3 is initially adjusted, and the new cable 3 can reduce up to 30% offset distance and 50% peak tension. The results also found that the relative rotational motion of the M4 is not sensitive to stiffness properties, which means the future PTO selection could be independent of the mooring cable.