FastFEM: Behaviour of fast ships in waves

快速船（10至60米）的使用在海上作业中已变得流行。它们现在出现在搜索和救援行动，监视，海岸警卫队活动，拦截和安全任务，禁毒和海盗行动，快速供应海上平台，以及船员运输和风电场维护。其主要优势是速度，而挑战是在轻度到重度的海上航道中保持高速安全的耐波性，同时保持这些船舶价格实惠，可靠，燃油效率和舒适。我们建议开发新的模拟工具，快速船舶和周围的波浪在破碎的海洋动力学，并验证这些模拟先进和新颖的拖曳水池实验室experiments.Classical计算的波浪是基于（非）线性势流波理论。如果采用精确的数值方法，这种模拟是相当好的，但由于势流的存在，这种模拟永远不能处理波浪破碎。此外，三维势流波代码需要在计算上变得更有效。这需要进一步的科学发展（荷兰特文特大学Jaap货车der Vegt和Onno Bokhove的工作包WP 1），特别是当波浪和船舶动力学完全非线性耦合时，如所提议的那样。WP 1的另一个关键问题是在我们部分现有的间断Galerkin有限元方法（DGFEM）中保留波动动力学的变分公式，以确保数值稳定性。我们的第一个创新是模拟船舶周围的波浪破碎，以及传入的破碎波，采用一种新的先进的水-空气混合物单相混合物理论（在利兹大学的WP 2中）。与其他可以处理波浪破碎的数值方法（如流体体积法和光滑粒子流体动力学）相比，我们的方法不会导致（不必要的）数值波浪阻尼光滑波的区域。我们的第二个创新是，新的方法是通过设计构造，包括我们的（变）势流限制与非线性船舶动力学。因此，这种新的方法，快速船舶在破浪不要求DGFEM的组合船舶和势流波动力学也充分发展（在WP 1）。重要的是对先进的和新的拖曳水池实验的两个（集成）模拟工具的预期验证。除了数值验证之外，这些拖曳水池实验（在荷兰德尔夫特理工大学的WP 3中，由Rene Huijsmans进行）以快速船舶周围的测量（非线性和破碎）波浪环境、船体压力以及船上加速度的形式向用户提供直接和新的数据。我们的用户将直接使用这些实验室测量结果：Damen Shipyards、MARIN、皇家荷兰海军、皇家荷兰救援组织（KNRM）、必维国际检验集团和劳埃德船级社，而支持新船体设计的拟议模拟工具将形成持续的投资。

The use of fast (10 to 60m) ships has become popular in maritime operations. They nowadays emerge in search and rescue operations, surveillance, Coast Guard activities, interceptor and security missions, anti drugs and piracy actions, in fast supply to offshore platforms, and for crew transport and wind farm maintenance. The main advantage is their speed, while the challenge is to maintain safe seakeeping at high speeds in mild to heavy seaway, while also keeping these ships affordable, reliable, fuel efficient and comfortable. We propose to develop new simulation tools for the dynamics of fast ships and surrounding waves in breaking seas, and to validate these simulations with advanced and novel towing tank laboratory experiments.Classical calculations of waves are based on (non)linear potential flow wave theory. Such simulations are quite good provided accurate numerical methods are used, but can never deal with wave breaking due to the potential flow Ansatz. In addition, potential flow wave codes in three dimensions need to become computationally more efficient. This requires further scientific development (work package WP1 at the University of Twente, The Netherlands by Jaap van der Vegt with Onno Bokhove), especially when wave and ship dynamics are fully and nonlinearly coupled, as proposed. Another key issue in WP1 is preservation of the variational formulation of wave dynamics, to ensure numerical stability, within our partially existing discontinuous Galerkin finite element methodology (DGFEM). Our first innovation is to simulate wave breaking around the ships, as well as incoming breaking waves, with a new, advanced single-phase mixture theory for the water-air mixture (in WP2 at the University of Leeds). In contrast to other numerical methods that can deal with wave breaking (such as Volume of Fluid methods and Smoothed Particle Hydrodynamics), our method does not lead to (unwanted) numerical wave damping in areas with smooth waves. Our second innovation is that the new method is by design constructed to include our (variational) potential flow limit with nonlinear ship dynamics. Hence, this new methodology for fast ships in breaking seas does require that the DGFEM for the combined ship and potential flow wave dynamics is fully developed as well (in WP1). Essential is the anticipated validation of both (integrated) simulation tools against advanced and new towing tank experiments. Beyond the numerical validation, these towing tank experiments (in WP3 at Delft University of Technology, The Netherlands by Rene Huijsmans) provide direct and new data to the users in the form of the measured (nonlinear and breaking) wave environment around fast ships, pressures on their hulls as well as onboard accelerations. These laboratory measurements will be directly used by our users: Damen Shipyards, MARIN, Royal Netherlands Navy, Royal Netherlands Rescue Organisation (KNRM), Bureau Veritas, and Lloyds Register, while the proposed simulation tools supporting new hull designs will form a sustained investment.