Modelling Marine Renewable Energy Devices; Designing for Survivability

该项目的主要目的是利用经过实验观测和全尺寸原型数据验证的数值模型来评估WECs的极端波浪载荷。项目团队结合了在极端波浪研究（帝国理工学院）、波浪能量转换器（贝尔法斯特女王大学）和数值模拟（曼彻斯特城市大学）方面具有丰富经验的机构，形成了一个强大而平衡的联盟。他们将得到一个指导委员会的支持，该委员会由一些关键的行业从业者和利益相关者组成，带来来自设备开发商、认证机构和海上行业的广泛背景。在设计波浪能转换器（WECs）时，科学家和工程师面临着必须在两个相互竞争的标准之间妥协的挑战。动力起飞，所有相关的机械和电气部件必须针对年平均海况或标称海况进行优化。与此同时，所有这些组件都必须承受大风暴事件，其中施加的流体载荷比名义海况高得多。一个成功的设计必然会平衡这两个标准。在早期设计阶段（在昂贵的小型或大型物理模型测试之前）确定这种平衡需要准确、可靠和有效的数值模型，适合这两种设计标准。生存能力决定了WEC的长期成功，必须在设计时加以解决。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，线性模型无法预测流体的运动学。因此，恶劣海况下波浪荷载的数值模拟具有挑战性；载荷直接受到底层流体运动学的影响。此外，波浪冲击、波浪破碎和空气夹带的发生也带来了额外的挑战。波浪非线性的准确描述，结合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带来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以下基础之上：(i) Met-Ocean的最新进展，为数值模拟和实验模拟提供现实的投入；（ii）基于分层方法的数值模拟；从线性和完全非线性的位势流模型到完全非线性的粘性流解算器（iii）使用最先进的波浪测试设施进行广泛的实验研究，适用于浅水和中/深水条件（iv）与原型wecs加载相关的现场数据进行比较。数值模型的结果将进行分析，以指导特定模型的适用性。以及与极端负载缩放相关的问题。这将使基于所采用的建模技术的极端载荷的不确定性的估计成为可能。研究方案最初侧重于两种一般设备类型，并将制定将这些模型应用于其他WECs的准则。总之，该项目采用双轨方法，结合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.