Abstract This study focuses on the formation and detachment of a leading edge vortex (LEV) appearing on an airfoil when its effective angle of attack is dynamically changed, inducing additional forces and moments on the airfoil. Experimental measurements of the time-resolved velocity field using Particle Image Velocimetry (PIV) are complemented by a computational study using an URANS (Unsteady Reynolds-Averaged Navier–Stokes) framework. In this framework a transition-sensitive Reynolds-stress model of turbulence, proposed by Maduta et al. (2018), which combines the near-wall Reynolds-Stress model by Jakirlic and Maduta (2015) and a phenomenological transition model governing the pre-turbulent kinetic energy by Walters and Cokljat (2008), is employed. Combined pitching and plunging kinematics of the investigated flat plate airfoil enable the effective inflow angle to be arbitrarily prescribed. A qualitative assessment of flow fields and a quantitative comparison of LEV characteristics in terms of its center position and circulation as well as an investigation of the mechanism causing the vortex to stop accumulating circulation revealed close agreement between the experimental and simulation results. Further considerations of the lift contribution from the pressure and suction side of the airfoil to the overall lift indicates that the qualitative lift evolution is reproduced even if the pressure side contribution is neglected. This reveals important characteristics of such airfoil dynamics, which can be exploited in future experimental studies, where direct aerodynamic force and moment measurements are greatly inhibited by dominating inertial forces.

中文翻译：

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同时俯仰和俯冲运动的平板上前缘涡的形成和分离：实验和计算研究

摘要 本研究的重点是当机翼的有效攻角动态改变时，机翼上出现的前缘涡 (LEV) 的形成和分离，从而在机翼上产生额外的力和力矩。使用粒子图像测速法 (PIV) 对时间分辨速度场的实验测量得到了使用 URANS（不稳定雷诺平均纳维 - 斯托克斯）框架的计算研究的补充。在这个框架中，由 Maduta 等人提出的湍流的过渡敏感雷诺应力模型。(2018) 结合了 Jakirlic 和 Maduta (2015) 的近壁雷诺应力模型和 Walters 和 Cokljat (2008) 的控制湍流前动能的现象学转换模型。所研究的平板翼型的俯仰和俯冲运动学相结合，可以任意规定有效流入角。流场的定性评估和 LEV 特性在其中心位置和循环方面的定量比较，以及导致涡流停止累积循环的机制的研究表明，实验和模拟结果非常吻合。进一步考虑从翼型的压力侧和吸力侧对整体升力的升力贡献表明，即使忽略压力侧贡献，定性升力演变也会重现。这揭示了这种翼型动力学的重要特征，可以在未来的实验研究中加以利用，