Abstract This paper presents a CFD-RANS investigation of the effect of the skeg hydrodynamics on the manoeuvrability of an Azimuth Stern Drive Escort Tug. This study is devoted to identifying a proper mathematical model to be included in a dynamic manoeuvring simulator. The hydrodynamic problem is therefore decomposed in the hull and skeg components. The hydrodynamic characteristics of the skeg were so explored by varying its span and chord systematically, allowing deep insight into the physics of both components and their mutual interaction. The distribution of the forces acting on hull and skeg were studied in detail in their dependence from the skeg geometrical characteristics. Suitable mathematical formulations for the skeg forces were implemented in an MMG-like manoeuvring model-based onto the CFD captive simulations. Lastly, the impact on the tug’s manoeuvrability of the previously mentioned variations was then investigated. Turning, Zig-Zag, Escort Capability, Escort Mirror ability and Escort Stability manoeuvres were simulated. The results of these manoeuvres are presented, showing the great potential of this manoeuvring model in representing a wider class of Escort tugs.

中文翻译：

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护航拖轮机动特性数值分析——第二部分：艉鳍效应

摘要 本文介绍了尾艉水动力对 Azimuth Stern Drive Escort Tug 操纵性影响的 CFD-RANS 研究。这项研究致力于确定一个合适的数学模型，以包含在动态操纵模拟器中。因此，水动力问题在船体和艉艉组件中分解。通过系统地改变其跨度和弦长来探索尾艉的流体动力学特性，从而深入了解两个组件的物理特性及其相互作用。详细研究了作用在船体和艉艉上的力的分布与艉艉几何特征的相关性。在基于 CFD 俘获模拟的类似 MMG 的机动模型中实施了适用于艉鳍力的合适数学公式。最后，然后研究了前面提到的变化对拖船操纵性的影响。模拟了转弯、之字形、护航能力、护航镜能力和护航稳定性机动。展示了这些机动的结果，显示了这种机动模型在代表更广泛的护航拖船方面的巨大潜力。