Abstract The offshore floating wind turbines (OFWT) inevitably experience yawed flows, which result in fluctuations in the angle of attacks (AOAs) of the airfoils and therefore considerably impact the aerodynamics. In this paper, the AOA of the blade of a horizontal OFWT under static and dynamic yawed conditions are investigated using the Free Vortex Method (FVM). Results show that the AOA fluctuation under yawed conditions could be attributed to three effects: the blade advancing & retreating effect, the non-uniform induction effect and the upwind & downwind yawing effect. At a positive yaw angle, the blade advancing & retreating effect results in a maximum AOA at the azimuth of 0°. This effect is more dominant for the inboard airfoils than the outboard ones. The non-uniform induction effect results in a maximum AOA at 90° for inboard airfoils while at 270° for outboard ones. This effect is more evident for the outboard blade segments. When the OFWT experiences platform yawing motion or during the dynamic yawing process, the upwind & downwind yawing effect occurs. This effect increases the AOA when the blade is yawing upwind and vice versa. It is more dominant for outboard airfoils and it increases as the yawing rate augments.

中文翻译：

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静动态偏航条件下水平轴海上浮动风力机叶片迎角数值研究

摘要 海上浮动式风力发电机（OFWT）不可避免地会经历偏航流，这会导致翼型迎角（AOA）的波动，从而对空气动力学产生重大影响。在本文中，使用自由涡流法 (FVM) 研究了静态和动态偏航条件下水平 OFWT 叶片的迎角。结果表明，偏航条件下的迎角波动可归因于三种效应：叶片进退效应、非均匀诱导效应和迎风下风偏航效应。在正偏航角时，叶片进退效应导致方位角为 0° 处的最大迎角。内侧翼型的这种效应比外侧翼型更显着。非均匀感应效应导致内侧翼型的最大迎角为 90°，而外侧翼型为 270°。这种效果对于外侧叶片段更为明显。当OFWT经历平台​​偏航运动或在动态偏航过程中，会发生逆风和顺风偏航效应。当叶片逆风偏航时，这种效果会增加迎角，反之亦然。它对舷外机翼更占优势，并且随着偏航率的增加而增加。