Drag Optimisation of Ship Shapes (DROPSS)

国际航运承担着约90%的全球贸易运输。航运的主导作用可归因于每吨每公里运输货物的低燃料消耗。然而，仅仅是45,000 - 50,000艘运营商船的规模就使航运的环境和经济方面成为许多优化工作的重点。海运污染以及大约50%的航运直接运营成本与燃料消耗有关，而燃料消耗又受船舶阻力的影响。后者在很大程度上是由稳定的水动力贡献控制的（估计75%），即平静水中的波浪阻力和沿湿润表面的摩擦阻力。从商业和环境的角度来看，减少这些阻力贡献的方法，即使每英里减少几个，都是非常值得赞赏的。目前的建议是关于一个计算框架的发展，为自由浮动船体暴露于非混相两相流的水动力形状优化。注意力集中在无参数优化环境下基于梯度的伴随方法。重点放在波浪和摩擦阻力在弗劳德-和雷诺-数字的实际利益。具体的兴趣是指(i)精确和强大的伴随两相流模型，包括（ii）包括动态浮动方面，（iii）一种新的减少伴随湍流处理和（iv）改进的无cad形状参数化，用于受制造限制的部分湿润形状。应用程序将集中在经常检查的集装箱船和钝离岸供应船。结果将转移到其他海洋工程应用的优化，例如设计近岸操作可再生能源设备，收集靠近自由表面的浪涌区域的海浪。

International shipping is responsible for the transport of around 90% of the global trade. The dominant role of shipping is attributable to the low fuel consumption per tonne*km of transported cargo. However, the mere magnitude of around 45-50 thousand operating merchant vessels puts environmental and economic aspects of shipping into the focus of many optimisation efforts. The seaborne pollution as well as approximately 50% of the direct operating costs for shipping are related to fuel consumption, which in turn is governed by the resistance of the vessel. The latter is largely controlled (75% at a guess) by steady hydrodynamic contributions, i.e. the wave drag in calm water and the friction drag along the wetted surface. Means to reduce these drag contributions, even by a few per mille, are highly appreciated from commercial and environmental perspectives.The present proposal is concerned with the development of a computational framework for the hydrodynamic shape optimisation of free-floating ship hulls exposed to immiscible two-phase flows. Attention is confined to gradient-based adjoint methods in a parameter-free optimisation environment. Emphasis is given to wave and friction drag at Froude- and Reynolds-numbers of practical interest. Specific interest refers to (i) accurate and robust adjoint two-phase flow models including (ii) the inclusion of dynamic floatation aspects, (iii) a novel reduced adjoint turbulence treatment and (iv) an improved CAD-free shape parameterization for partially wetted shapes subjected to manufacturing constraints. Applications will focus on a frequently investigated container vessel and a blunt offshore supply vessel. Results will be transferable to the optimisation of other marine engineering applications, e.g. the design of near-shore operating renewable energy devices harvesting ocean waves in the surge zone close to a free surface.