Aerodynamics of static and dynamic stall - An experimental study

大多数翼型都在大迎角下运行，以最大限度地提高气动性能，因为它们容易分离和失速，特别是当它们在各种条件下运行时。对于风力涡轮机、螺旋桨和其他旋转机械来说尤其如此。在这种情况下，与低迎角相比，流动机制和噪声产生特征有很大不同。我们的知识和理解的机制，以及我们的能力，以预测这些空气动力学现象和噪声源是有限的。在这个项目中，目标是进行详细的近场流实验和远场噪声测量，以发展对分离和失速存在的空气动力学和空气声学的新认识。三维粒子图像测速将在水道中的箔片上进行，以阐明空气动力学机制。三维数据将与新的数据同化策略相结合来确定整个油田的压力。该压力场将用于确定流动中速度和压力之间的关系，也用于预测箔片产生的远场噪声。这种预测可以与在消声风洞中进行的实验进行比较，在消声风洞中可以直接测量远场噪声。最终，该项目生成的高保真数据将用于确定在大迎角下产生不同气动力和噪声源的流动机制。

Most aerofoils are operated at high angles of attack to maximise aerodynamic performance where they are prone to separation and stall, especially when they are operating under varied conditions. This is especially true for wind turbines, propellers and other rotating machinery. In these situations, the flow mechanisms and the noise generating features are substantially different compared to lower angles of attack. Our knowledge and understanding of the mechanisms as well as our ability to predict these aerodynamic phenomena and noise sources is limited. In this project, the goal is to carry out detailed near-field flow experiments as well as far-field noise measurements to develop new understanding of the aerodynamics and aeroacoustics in the presence of separation and stall. Three-dimensional Particle Image Velocimetry will be performed over a foil in a water channel to elucidate the aerodynamic mechanisms. The 3D data will be combined with new data assimilation strategies to determine the full-field pressure. This pressure field will be used to determine relationship between velocity and pressure across the flow and also used to predict the far-field noise generated by the foil. This prediction can be compared against experiments carried out in an anechoic wind tunnel where far-field noise can be measured directly. Ultimately, the high-fidelity data generated in this project will will then be used to identify flow mechanisms that contribute to the different aerodynamic force and noise sources at high angles of attack.