New Generation Modelling Suite for the Survivability of Wave Energy Convertors in Marine Environments (WavE-Suite)

虽然波浪能转换器（WECs）的研究历史悠久，但仍然存在许多挑战，这使得开发有效，可靠和经济可行的WECs变得困难。其中一个挑战是缺乏强大的建模工具来评估在极端海洋环境下造成极端载荷和大响应的WECs的生存能力。WECs的生存能力不仅在设计阶段需要考虑，而且在操作时也需要考虑，以最大限度地利用能量，最大限度地降低损坏的风险。为了评估和分析白蚀细胞的生存能力，必须确定生存条件，量化白蚀细胞的载荷和响应，并表征白蚀细胞在生存条件下的压力和速度场。确定WECs的生存条件不仅需要考虑强风暴，还需要考虑短陡海中WECs的载荷和响应，这与其他海上结构可能只需要考虑产生最大浪高的强风暴不同。载荷和响应的高精度量化必须考虑破波和粘度，这将为概念设计提供主导因素，并决定设备是否需要关闭。WECs压力场和速度场的表征需要足够详细地解析具有涡结构的两相流，这将为结构和部件的设计提供信息。此外，由于生存条件下的波是高度非线性的，因此必须在大范围内对其进行长时间的传播模拟，以使其充分进化。因此，分析WEC生存能力的数值模拟工具应具有处理破碎波和两相流的能力，并能准确估计湍流状态下粘度的影响。与此同时，这些工具必须足够快，以便工程师能够在实际的时间尺度内模拟设计案例。目前已有许多精度和效率各不相同的数值模型，但没有一种能充分处理实际中遇到的极端条件。有些模型是相位平均的，计算效率高，但不够精确。有些模型是基于势理论或粘性理论的相分辨模型。最先进的势模型是完全非线性的，比粘性模型快得多，但不能处理波浪破碎和湍流，而波浪破碎和湍流是WECs中经常发生的。粘性模型在理论上可以处理物理现象，但通常在计算上非常昂贵，可能还存在不必要的数值耗散。该项目将通过结合不同的模型，提出新的数值方法和机器学习技术，开发一种新的数值建模套件，这将更准确，需要更少的计算量。建模套件将能够根据波浪的非线性程度及其与WECs的相互作用自动进行完全非线性模拟和线性模拟。新的建模套件将通过实验室和海上实际设备的WEC模型测量数据进行验证，并将用于评估与WEC生存能力和可靠性相关的参数。在研究期间，我们会成立一个顾问委员会，就具体的研究课题提出建议，并定期举行项目会议/工作坊，以吸引持份者的兴趣和传播研究成果。我们的项目合作伙伴将被邀请成为顾问委员会的成员，并参加或参与会议/研讨会。在这个项目中，将为不同类型的WECs创建数据库，供公众访问。

Although there is a long history of research of wave energy convertors (WECs), there are still many challenges that make it difficult to develop effective, reliable and economically viable WECs. One of the challenges is the lack of robust modelling tools to assess survivability of WECs under extreme marine environments that cause extreme loads and large responses. Survivability of WECs needs to be concerned not only in the design stage but also when operational to maximise the amount of harnessed energy and minimise the risk of damage. To assess and analyse the survivability of WECs, one must identify survival conditions, quantify loadings and responses of WECs and characterise the pressure and velocity field of WECs under survival conditions. Identification of survival conditions for WECs requires not only the consideration of severe storms but also of loads and responses of WECs in shorter steep seas, which is different from that for other offshore structures that may just need to consider severe storms giving the largest wave heights. High precision quantification of loadings and responses of WECs must consider wave breaking and viscosity, which will provide dominate factors for conceptual design and to determine if the device needs to be shut down. Characterisation of the pressure and velocity fields of WECs needs to resolve two-phase flow with vortex structures to sufficient detail, which will provide information for structural and components design. In addition, as the waves in the survival conditions are highly nonlinear, they must be simulated for a long propagating duration in a large domain to allow them to sufficiently evolve. Therefore, the numerical modelling tools for analysing WEC survivability should have the capability of dealing with breaking waves and two-phase flow and accurately estimating the effect of viscosity in turbulent states. In the meantime, the tools must be fast enough so that engineers can simulate the cases within practical time-scales for design. Many numerical models with various levels of accuracy and efficiency exist, but none of them can adequately deal with the extreme conditions found in practice. Some models are phase-averaged, being computationally efficient but not sufficiently accurate. Some models are phased-resolved, based either on the potential theory or the viscous theory. The most advanced potential models are fully nonlinear and much faster than viscous models, but could not deal with wave breaking and turbulence which always occurs for WECs. The viscous models can theoretically deal with the physical phenomena but are generally very computationally expensive, perhaps also suffering from unwanted numerical dissipation. This project will develop a novel numerical modelling suite by combining different models and by proposing new numerical approaches and machine learning techniques, which will be more accurate and require less computational effort. The modelling suite will be able to automatically go up to fully nonlinear simulations and down to linear simulations depending on the level of nonlinearity of waves and their interaction with the WECs. The new modelling suite will be validated by data measured from WEC models in the laboratory and real devices at sea, and will be applied to assess the parameters relevant to the survivability and reliability of WECs. During the project, an advisory board will be set up to give the suggestions on specific research topics, and regular project meetings/workshops will be held to attract the interests of WECs stakeholders and disseminate the research outcomes. Our project partners will be invited to be a member of the advisory board and to attend or contribute to the meetings/workshops. Databases for different types of WECs will be created during this project, which will be accessible by general public.