Measurements of static and dynamic mooring line damping and their importance for floating WEC devices
Measurements of static and dynamic mooring line damping and their importance for floating WEC devices
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DOI：
10.1016/j.oceaneng.2007.04.002
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发表时间：
2007-10
影响因子：
5
通讯作者：
L. Johanning;George H. Smith;J. Wolfram
中科院分区：
文献类型：
--
作者：
L. Johanning;George H. Smith;J. Wolfram
系泊缆的动态响应将是将其用于波能转换器（WEC）的位置保持时需要考虑的主要因素。由于WEC的尺寸相对较小，并且它们系泊在相对较浅的沃茨中，因此波浪、潮汐和水流的影响可能比其他浮动海上系统更重要。轴线拉伸和高频“顶端”动力学可以重要地修改阻尼和顶端载荷。如果要考虑设备的“农场”，则海洋空间的限制可能需要设备相对密集地包装。这将意味着系泊的“足迹”应受到约束，以确保每个装置的系泊不干扰，这将对缆绳承受的载荷具有重要意义。还必须考虑系泊系统如何改变WEC的响应，从而改变其从波浪中提取动力的能力。与典型的海上系统不同，WEC设备的系泊设计必须考虑可靠性和生存能力，以及确保有效能量转换的需要。这里考虑的是用于WEC的锚链系泊的设计和操作。系泊线阻尼的一般实验测量是在赫瑞瓦特大学的波浪盆地中进行的，比例尺为1：10。测量是在单系泊缆上进行的，包括轴向拉伸和高端动力学研究。实验室程序的设计类似于先前在24米水深的“全”规模进行的试验。测量结果也与数值研究进行了比较。WEC装置的实验结果支持这样的结论，即动态系泊缆运动将是一个重要变量，需要在设计中仔细考虑。
The dynamic response of the mooring line will be a dominant factor to consider in their use for the station keeping of a wave energy converter (WEC). Due to the relatively small size of WECs and their being moored in relatively shallow waters the effect of waves, tide and current can be of greater significance than for other floating offshore systems. Axial line stretching and high-frequency ‘top-end’ dynamics can importantly modify damping and top-end loading. If a ‘farm’ of devices is to be considered then limitations in sea space may necessitate that the devices be relatively densely packed. This will mean that the ‘footprint’ of the mooring should be constrained, to ensure that the moorings from each device do not interfere and this will have great significance for the loading experienced by the line. One must also consider how the mooring system might change the response of the WEC and so alter its ability to extract power from the waves. Unlike a typical offshore system, the design of moorings for a WEC device must consider reliability and survivability, and the need to ensure efficient energy conversion. The design and operation of a chain mooring for a WEC is considered here. Generic experimental measurements of mooring line damping were conducted in the Heriot-Watt University wave basin at a scale of 1:10. The measurements were conducted on a single mooring line for surge motions and include the study of axial stretching and high top-end dynamics. The laboratory procedures were designed to resemble tests undertaken earlier at ‘full’ scale in 24m water depth. The measurements were also compared with numerical studies. The experimental findings for WEC devices, supports the conclusion that dynamic mooring line motion will be an important variable, needing to be considered carefully within the design.