Modelling Marine Renewable Energy Devices; Designing for Survivability

该项目的主要目标是使用与实验观测和全尺寸原型数据相验证的数值模型来评估西部环流中心的极端波浪载荷。该项目团队结合了在极端海浪(帝国理工学院)、波能转换器(贝尔法斯特女王大学)和数值模拟(曼彻斯特都市大学)方面拥有丰富经验的机构，组成了一个强大且平衡的财团。它们将得到一个由多名关键行业从业者和利益相关者组成的指导委员会的支持，该委员会将从设备开发商、认证机构和离岸行业引入广泛的背景。在设计波能转换器(WEC)时，科学家和工程师面临着不得不在两个相互竞争的标准之间妥协的挑战。动力输出，所有相关的机械和电气部件必须针对年平均或标称海况进行优化。与此同时，所有这些部件都必须经受住大风暴事件，与标称的海况相比，施加的流体载荷要高得多。一个成功的设计必然是一个平衡这两个标准的设计。在早期设计阶段(在昂贵的小型或大型物理模型测试之前)确定这样的平衡需要准确、可靠和高效的、适合这两种设计标准的数值模型。生存能力定义了WEC的长期成功，必须通过设计来解决。水波表现出固有的非线性，这是波浪陡度的函数。在恶劣的海况下，线性模型不能很好地预测流体运动。因此，严重海况下波浪载荷的数值模拟是具有挑战性的；载荷直接受到基本流体运动学的影响。此外，海浪冲击、海浪破碎和空气卷吸的发生也带来了额外的挑战。对波浪非线性的准确描述，加上模拟局部载荷效应的能力，是数值模拟成功的关键。项目团队在数值模型开发方面引入了世界领先的专业知识。事实上，这些模型现在已经达到了与实验数据直接比较的复杂程度。综合研究方案建立在(1)大洋海洋的最新进展的基础上，为数值模拟和实验模拟提供了现实的输入；(2)基于分层方法的数值模拟，从线性和完全非线性势流模型到完全非线性粘性流动解算器(Iii)使用适用于浅水和中/深水条件的最先进的波浪测试设备进行广泛的实验研究(Iv)与与原型WEC加载有关的现场数据的比较将对数值模型的结果进行分析，以指导特定模型的适当性以及与极端负载比例相关的问题。这将使人们能够根据所采用的建模技术来估计极端负荷下的不确定性。研究方案最初侧重于两种通用装置类型，并将制定将这些模型应用于其他WEC的指导方针。总而言之，该项目是以双轨方式确定的，结合了先进的数值模型和仔细的实验实践；其结果将有助于促进波能转换器的大规模部署。

The primary aim of the project is the assessment of the extreme wave loads on WECs using numerical models validated against experimental observations and full-scale prototype data. The project team combines institutions with significant experience in research into extreme waves (Imperial College), wave energy converters (Queen's University Belfast) and numerical modelling (Manchester Metropolitan University), forming a strong and well-balanced consortium. They will be supported by a steering committee comprising a number of key industrial practitioners and stakeholders, bringing in a wide range of backgrounds from device developers, certifying bodies and the offshore industry. In designing wave energy converters (WECs), scientists and engineers face the challenge of having to compromise between two competing criteria. The power take-off, with all associated mechanical and electrical components having to be optimised for an annual average or nominal sea state. At the same time all these components will have to withstand large storm events, where the applied fluid loads are substantially higher compared to the nominal sea state. A successful design is inevitably characterised by one that balances these two criteria. Identifying such a balance at an early design stage (prior to expensive small or large scale physical model testing) requires accurate, reliable and efficient numerical models appropriate to both design criteria. Survivability defines the long term success of a WEC, and must be addressed by design.Water waves exhibit inherent nonlinearities, which are functions of the wave steepness. In severe sea states, linear models fail to predict the fluid kinematics. As a result, the numerical modelling of wave loading in severe sea states is challenging; the loads being directly affected by the underlying fluid kinematics. Further, the occurrences of wave impacts, wave breaking and air entrainment pose additional challenges. An accurate description of wave nonlinearities, combined with the ability to model local loading effects, is key to the success of the numerical modelling. The project team brings in world-leading expertise in the development of numerical models. In fact, these models have now reached a level of sophistication where a direct comparison with experimental data is practical.The integrated research programme builds upon(i) The latest advances in Met-Ocean, providing a realistic input to both the numerical and the experimental modelling (ii) Numerical modelling based on a hierarchical approach, ranging from linear and fully nonlinear potential flow models to fully nonlinear viscous flow solvers(iii) Extensive experimental investigation using state-of-the-art wave testing facilities appropriate to both shallow and intermediate / deep water conditions(iv) Comparisons with field data relating to loading of prototype WECsThe results of the numerical models will be analysed to provide guidance on the appropriateness of particular models, as well as issues associated with the scaling of extreme loads. This will enable an estimation of the uncertainty in extreme loads based on the modelling technique adopted. The research programme initially focuses on two generic device types, and guidelines for the application of the models to other WECs will be developed. In summary, the project is defined by a twin-track approach, combining advanced numerical models and careful experimental practice; the results of which will help to facilitate the large-scale deployment of wave energy converters.