Unsteady velocities of energetic tidal currents : an investigation into dynamic flow effects on lifting surfaces at field and experimental scale
Unsteady velocities of energetic tidal currents : an investigation into dynamic flow effects on lifting surfaces at field and experimental scale
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高能潮汐流的不稳定速度：现场和实验规模的动态流对升力面影响的研究
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
S. Harding
中科院分区：
文献类型：
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作者：
S. Harding
潮流发电是一个新兴行业，具有以可预测和可持续的方式为英国能源供应做出贡献的潜力。这项技术的发展需要在充满活力和挑战的海洋环境中以具有成本效益的方式在海底安装能量转换系统。为将潮汐能转换器固定在海床上而开发的一个概念是主动重力基座(AGB)，与现有的紧固方法相比，它可能会减少安装成本和时间。本文探讨了这一概念在非恒定流条件下的性能。潮流的动态行为是由一系列因素驱动的，从天体的引力到湍流涡旋的高频波动。本文在两个大的时间尺度下考虑了AGB概念对潮流不稳定的响应：平均半日循环的方向性和给定平均流速的高频变化。潮流的方向和速度之间的相关性是使用英国北部水域的海军图提供的每小时平均数据来评估的。所得到的方向性模型被用来预测AGB在一系列准定常流动条件下的性能。通过与华盛顿大学和太平洋西北国家实验室合作，获得了一个潜在潮汐能站点的高频速度测量结果。这一数据被用来估计每年可预期的平均速度的最大扰动。在爱丁堡大学的循环水槽内建立了一套实验装置，用于测试可控二维流动扰动产生的动态载荷。这是成功地实现了使用配置双俯仰箔与独立的运动控制。利用翼面尾迹的涡模型预测了翼面俯仰角与速度摄动时间序列之间的关系。这种构型能够在0.06≤k≤1.9的折减频率范围内产生显著的气流波动，其峰值阵风强度为Ig=0.5。数值解与实验结果进行了对比验证。
The generation of electricity from tidal currents is an emerging industry with the potential to contribute to the UK energy supply in a predictable and sustainable way. The development of the technology requires the cost effective subsea installation of energy conversion systems in an energetic and challenging marine environment. One concept developed for the fastening of tidal energy converters to the seabed is the Active Gravity Base (AGB), which offers potential reductions in installation cost and time, relative to existing fastening methods. The performance of this concept in response to unsteady flow conditions is explored within this thesis. The dynamic behaviour of a tidal current is driven by a range of factors from gravitational forces of celestial bodies to high-frequency fluctuations of turbulent eddies. The response of the AGB concept to the unsteadiness of tidal currents is herein considered under the two broad time-scales; the directionality of the mean semi-diurnal cycle and the high frequency variations from a given mean flow velocity. The correlation between the direction and velocity of the tidal flow was assessed using hourly averaged data provided by the Admiralty Charts in the northern UK waters. The resulting directionality model was used to predict the performance of the AGB under a range of quasisteady flow conditions. High frequency velocity measurements of a potential tidal energy site were obtained through collaboration with the University of Washington and the Pacific Northwest National Laboratory. This data was used to estimate the maximum perturbation from the mean velocity that can be expected on an annual basis. An experimental facility was developed within the re-circulating water flume at the University of Edinburgh to examine the dynamic loads generated by controllable two-dimensional flow perturbations. This was successfully achieved using a configuration of twin pitching foils with independent motion control. A relationship between the foil pitch angle and velocity perturbation time series was predicted using a vortex model of the foil wakes. This configuration was shown to be able to generate significant flow fluctuations within the range of reduced frequencies 0.06 ≤ k ≤ 1.9, with a peak gust intensity of Ig = 0.5. The numerical solution was validated against experimental results.
影响因子：
8.7
作者：
Harding S
通讯作者：
Harding S
影响因子：
3.7
作者：
Harding S
通讯作者：
Harding S