Unsteady Aerodynamics of Wings in Extreme Conditions

目前，飞机设计师必须为最坏的情况加上安全因素进行设计。这种最坏的情况总是在性能信封的边缘，并与极端操作和/或阵风有关。在这些情况下的气动流动具有高度不稳定、分离的流动区域和可能的涡旋相互作用的特点。尽管这些极端情况在决定飞机结构方面很重要，但人们对这些高度分离的流动知之甚少，目前的理论模型在预测非定常力方面很差。该项目的目的是实现一个完整的非定常气动行为的通用机翼在极端条件下，包括在失速角附近的俯冲运动的理解。这种对涡旋流及其对气动力产生的影响的改进知识将用于开发精确的降阶模型，提高数值模拟的准确性，并开发有效的高频负载控制策略。拟议的项目将通过结合实验（巴斯大学）和计算（南安普顿大学）的方法，使用最先进的设施来解决这些问题。这种对高度分离气流的深入了解、精确的降阶模型和精确的数值模拟，将有助于飞机设计师消除围绕性能极限飞行的一些不确定性。此外，高频负载控制策略是控制和限制这些极端负载的潜在可行方法。因此，飞机设计不仅可以预测精度更高，而且可以控制。这两种元素都将使飞机变得更轻、更省油。

Currently aircraft designers must design for the worst case scenario plus a safety factor. This worst case scenario is always at the edge of the performance envelope and is associated with extreme manoeuvres and /or gusts. The aerodynamic flow over thse cases is characterised by highly unsteady, separated flow regions and possibly vortical interactions. Despite the importance of these extreme cases in dictating the aircraft structure very little is known about these highly separated flows and the current theoretical models are poor at predicting the unsteady forces. The aim of this project is to achieve a complete understanding of the unsteady aerodynamic behaviour of generic wings in extreme conditions involving plunging motion near the stall angle. This improved knowledge of the vortical flows, and their influence on aerodynamic force generation, will be used to develop accurate reduced-order models, to improve the accuracy of numerical simulations and to develop effective high-frequency load control strategies. The proposed project will address these aspects through a combined experimental (University of Bath) and computational (University of Southampton) approach using state of the art facilities.The benefits of this increased understanding of the highly separated flows, accurate reduced-order models and accurate numerical simulations will aid aircraft designers by removing some of the uncertainty that surrounds flight at the limits of the performance envelope. In addition, the high-frequency loads control strategies are a potentially feasible method of then controlling and limiting these extreme loads. Hence, the aircraft design can not only predict with greater accuracy but also control. Both elements will allow for lighter, more fuel efficient aircraft.