Abstract Large Eddy Simulations are reported on the flow around a rudder operating in the wake of a propeller. Results demonstrate the production of important spanwise flows within the boundary layer on the hydrofoil, mainly tied to the behavior of the largest coherent structures populating the propeller wake. The two branches of the hub vortex are shifted from the pressure towards the suction sides of the rudder. The pressure and suction side branches of the tip vortices move outward and inward, respectively. This phenomena increase the asymmetry between pressure and suction sides, with wider areas of the rudder surface affected by the propeller wake on the pressure sides. In the vicinity of the leading edge the main sources of turbulent fluctuations within the boundary layer on the hydrofoil are the two branches of the hub vortex, with also an evident signature of the tip vortices, especially on the suction sides, where they experience a stronger stretching. Moving from the leading edge towards the trailing edge both momentum and turbulence within the rudder boundary layer become obviously higher on the pressure sides than on the suction sides, because of the impingement operated by the propeller wake, whose azimuthal velocity is directed towards the pressure sides of the hydrofoil. Such effect is evident across the whole spanwise extent affected by the propeller wake, involving also the outer radii populated by the tip vortices. However, moving away from the surface of the hydrofoil the turbulent stresses become higher on the suction sides, due to the shear generated by the contraction of the propeller wake, which is instead expanding on the pressure sides.

中文翻译：

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跟随螺旋桨流过水翼

摘要 大涡模拟报告了在螺旋桨尾流运行的舵周围的流动。结果表明在水翼上的边界层内产生了重要的展向流动，主要与螺旋桨尾流中最大的连贯结构的行为有关。轮毂涡流的两个分支从压力向舵的吸力侧转移。尖端涡流的压力和吸力侧分支分别向外和向内移动。这种现象增加了压力侧和吸力侧之间的不对称性，受压力侧螺旋桨尾流影响的舵面面积更广。在前缘附近，水翼边界层内湍流波动的主要来源是轮毂涡的两个分支，还有明显的尖端涡流特征，尤其是在吸力侧，在那里它们经历了更强的拉伸。从前缘向后缘移动，舵边界层内的动量和湍流在压力侧明显高于吸力侧，这是由于螺旋桨尾流的冲击，其方位速度指向压力侧的水翼。这种效应在受螺旋桨尾流影响的整个展向范围内都很明显，还涉及由尖端涡流构成的外半径。然而，远离水翼表面的湍流应力在吸力侧变得更高，这是由于螺旋桨尾流收缩产生的剪切力，而不是在压力侧膨胀。