Modelling gust-encounters on UAVs with cyber-physical fluid dynamics

微型飞行器(MAV)是一种未来的遥感平台，其大小从大昆虫到小鸟不等。正在开发它们的目的是调查在更大的平台上很难或不可能访问的主题，或者在车辆必须不显眼的地方。例如，为搜救而开发的MAV可能能够在狭小或林区导航，而用于野生动物监测的MAV可能能够在不惊吓鸟类的情况下在鸟类附近操作。此外，MAV的小尺寸和低成本使其能够更多地执行传统的遥感任务，如环境和基础设施监测。然而，目前的MAV设计不能在露天运行，因为它们非常容易受到阵风的影响。因此，来自鸟类和昆虫等擅长驾驭风向变化的自然飞行物的灵感，已成为MAV开发的共同主题。使用与普通商用飞机相同的策略，小型生物飞行器不会保持在高空。取而代之的是，它们用翅膀来推动自己前进，并保持在高空；扑翼飞行必须用一套完全不同的工程工具来描述，这些工具可以解释扑翼复杂的、时变的运动。*拟议的研究将开发此类工程工具，特别侧重于了解阵风负荷。这些工具将在首先确定阵风遭遇的流动物理之后开发。这项物理研究将在水道中进行实验，在那里将使用阵风发生器将拍打的机翼暴露在非定常流动中。阵风载荷将通过机翼上的称重传感器进行测量，而机翼周围的流动将使用染料流动可视化和粒子图像测速仪进行观测。在确定阵风遭遇的物理过程并将其输入工程模型后，我们将能够改进实验设备以研究阵风，并开发新的方法来限制机翼在阵风中所经历的升力和阻力的变化。这项研究计划还将培养新的工程师成为流动物理和飞行力学方面的专家。

Micro-aerial vehicles (MAVs) are futuristic remote sensing platforms, ranging in size between that of large insect to a small bird. They are being developed to investigate subjects that would be difficult or impossible to access with a larger platform, or where the vehicle must be inconspicuous. For instance, an MAV developed for search and rescue may be able to navigate cramped or wooded areas, while an MAV meant for wildlife monitoring may be able to operate near birds without startling them. Moreover, the small size and low cost of MAVs allow for greater access to traditional remote-sensing tasks, such as environmental and infrastructure monitoring. However, current MAV designs cannot operate in the open air as they are very vulnerable to gusts. Inspiration from natural flyers such as birds and insects, which are adept at managing changing winds, has therefore become a common theme in MAV development. Small biological flyers do not stay aloft using the same strategies as common commercial aircraft. Instead, they use their wings to both propel themselves forward and to stay aloft; flapping-wing flight must be described with an entirely different set of engineering tools that account for the complex, time-varying motion of flapping wings. ***The proposed research will develop such engineering tools with a specific focus on understanding gusting loads. These tools will be developed after first determining the flow physics of gust encounters. This physical investigation will be carried out experimentally in a water channel, where a gust generator will be used to expose a flapping wing to unsteady flows. Gust loadings will be measured with a load cell in the wing, while the flow around the wing will be observed with dye-flow visualizations and Particle-Image Velocimetry. After determining the physics of the gust encounters, and after feeding this physics into an engineering model, we will be able to improve experimental facilities for the purposes of studying gusts and to develop new methods to limit the variations in lift and drag experienced by a wing exposed to gusts. This research program will also train new engineers to be experts in both flow physics and the mechanics of flight.