The pre-swirl stator (PSS), as a type of energy-saving device, has garnered increasing attention due to efforts aimed at global energy-saving and emission reduction. Owing to the influence of the stern profile, the wake field at the stern is complex, and the installation of such energy-saving appendages further increases its complexity. To explore the flow mechanism of a ship's wake field and the working principles of energy-saving appendages, this study used a scale model of a bulk carrier as its research object and conducted a wake field experiment with the help of the large underwater stereoscopic particle image velocimetry system at Harbin Engineering University. The wake field data of several sections were obtained, including the axial velocity, tangential velocity, average kinetic energy, vorticity, swirl strength, streamline, pulsating velocity, turbulent kinetic energy, and axial velocity at different radii. The wake field data with or without a PSS in the bare hull condition and with or without a PSS in the self-propelled condition were compared. The time-averaged flow field clearly demonstrated a “hook-like” velocity profile, bilge vortex, hub cap vortex, and other flow structures, as well as the flow details around the PSS. The results showed that the PSS could destroy the contour structure of the axial velocity, which mainly affects the range of 0.5–0.8R, making the flow field more uniform. The PSS has a certain influence on the flow field on the side without the stator blade and a great influence on the tangential velocity by producing a pre-swirl flow in a direction opposite to the propeller rotation in front of the propeller plane. This pre-swirl flow can increase the inflow of the propeller disk and improve the working conditions of the propeller. The PSS also has an influence on radial velocity; however, the influence degree and range are smaller than that on the tangential velocity. The PSS changed the water inflow direction, increased the interaction angle between the water flow and propeller blade, improved the wake conditions and propulsion performance, and was conducive to improving the working efficiency of the propeller. Moreover, the existence of a PSS reduced the local pulsating velocity and turbulent kinetic energy, benefiting the structural strength of the propeller.

预涡流定子（PSS）作为一种节能装置，在全球节能减排的努力中越来越受到关注。由于船尾剖面的影响，船尾尾流场较为复杂，安装此类节能附件进一步增加了其复杂性。为探讨船舶尾流场的流动机理和节能附件的工作原理，本研究以散货船的比例模型为研究对象，借助大型水下立体粒子图像进行尾流场实验。哈尔滨工程大学测速系统。获得了多个剖面的尾流场数据，包括轴向速度、切向速度、平均动能、涡度、涡流强度、流线、不同半径下的脉动速度、湍流动能和轴向速度。比较了在裸船体条件下有或没有 PSS 和在自航条件下有或没有 PSS 的尾流场数据。时均流场清楚地展示了“钩状”速度剖面、舱底涡、轮毂盖涡和其他流动结构，以及 PSS 周围的流动细节。结果表明，PSS可以破坏轴向速度的轮廓结构，主要影响0.5-0.8R范围，使流场更加均匀。PSS通过在螺旋桨平面前方产生与螺旋桨旋转相反方向的预旋流，对无静叶一侧的流场有一定影响，对切向速度有很大影响。这种预旋流可以增加螺旋桨盘的流入量，改善螺旋桨的工作条件。PSS 也对径向速度有影响；但其影响程度和范围均小于切向速度。PSS改变了进水方向，增大了水流与螺旋桨叶片的相互作用角，改善了尾流条件和推进性能，有利于提高螺旋桨的工作效率。此外，PSS 的存在降低了局部脉动速度和湍流动能，有利于螺旋桨的结构强度。其影响程度和范围小于对切向速度的影响。PSS改变了进水方向，增大了水流与螺旋桨叶片的相互作用角，改善了尾流条件和推进性能，有利于提高螺旋桨的工作效率。此外，PSS 的存在降低了局部脉动速度和湍流动能，有利于螺旋桨的结构强度。其影响程度和范围小于对切向速度的影响。PSS改变了进水方向，增大了水流与螺旋桨叶片的相互作用角，改善了尾流条件和推进性能，有利于提高螺旋桨的工作效率。此外，PSS 的存在降低了局部脉动速度和湍流动能，有利于螺旋桨的结构强度。