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

虽然波能转换器的研究已经有了很长的历史，但仍然存在许多挑战，使得开发有效、可靠和经济可行的波能转换器变得困难。挑战之一是缺乏可靠的建模工具来评估在造成极端负荷和巨大反应的极端海洋环境下WEC的生存能力。WEC的生存能力不仅需要在设计阶段关注，而且在运行时也需要关注，以最大限度地利用能量并将损坏风险降至最低。为了评估和分析水中细胞的生存能力，必须识别其生存条件，量化水中细胞的载荷和响应，并表征生存条件下水中细胞的压力场和速度场。确定WEC的生存条件不仅需要考虑严重的风暴，还需要考虑WEC在较短的陡峭海面上的载荷和响应，这与其他近海结构物不同，其他近海建筑物可能只需要考虑提供最大波高的严重风暴。WEC载荷和响应的高精度量化必须考虑波浪破碎和粘性，这将为概念设计和确定设备是否需要关闭提供主导因素。WECS压力场和速度场的表征需要对具有旋涡结构的两相流进行充分的解析，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，必须在大范围内对它们进行长时间的传播模拟，才能使它们充分演化。因此，用于分析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，并准确地估计湍流状态下粘性的影响。与此同时，工具必须足够快，以便工程师能够在实际时间尺度内模拟案例进行设计。存在许多具有不同精度和效率的数值模型，但它们都不能充分处理实际中发现的极端情况。一些模型是相位平均的，计算效率很高，但精度不够高。有些模型是分阶段分解的，要么基于位势理论，要么基于粘性理论。最先进的势能模型是完全非线性的，比粘性模型快得多，但不能处理WEC经常发生的波浪破碎和湍流。粘性模型在理论上可以处理物理现象，但通常计算非常昂贵，可能还会受到不必要的数值耗散的影响。该项目将通过组合不同的模型并提出新的数值方法和机器学习技术来开发一套新的数值模型，这些方法将更准确，需要更少的计算工作。建模套件将能够根据波的非线性程度及其与WEC的相互作用自动上升到完全非线性模拟和下降到线性模拟。新的建模套件将通过实验室中的WEC模型和海上真实设备测量的数据进行验证，并将用于评估与WEC的生存能力和可靠性有关的参数。在项目期间，将成立一个咨询委员会，就具体的研究主题提出建议，并定期举行项目会议/研讨会，以吸引世界经济共同体利益攸关方的兴趣，并传播研究成果。我们的项目伙伴将被邀请成为咨询委员会的成员，并出席会议/讲习班或为会议/讲习班作出贡献。在该项目期间，将为不同类型的世界经济共同体创建数据库，供公众查阅。

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.