Collaborative Research: The aerodynamic and metabolic costs and benefits of flow interactions in bird flight

最近对几种类型和大小鸟类的飞行力学的实地研究揭示了比以前认为的更多地利用环境能量(例如阵风、尾流和上升气流)来为飞行提供动力。然而，由于对鸟类的空气动力学、飞行成本和飞行力学的详细研究都是在气流平稳、稳定的风洞中进行的，因此人们对鸟类如何利用非定常流型知之甚少。在这个项目中，研究人员将通过测量飞行的能量成本、空气动力学和风洞中鸟类的拍打运动来填补这一认识空白，并将平滑流动条件与4种不同的非定常流动情况进行比较。这项研究还将测试车载式加速度计的使用，以作为相同大范围流动条件下飞行能量成本的替代测量，从而实现更准确的现场研究。这项研究将增加对非定常流动中的空气动力学以及小鸟的生态和进化的基本了解。进行这个项目需要生物学和工程学的跨学科结合。为了促进这个项目的教育目标，它包括一个本科生研究体验部分。在这个子项目中，来自全国各地的生物和工程学本科生申请暑期研究奖学金来参与这个项目。在这个项目中，PI和Co-PIs将应用最先进的新陈代谢空气动力学和加速计测量，以了解鸟类之间相互作用的能量成本或好处和潜在有益的流动结构，以及产生代谢结果的潜在空气动力学机制。流动模式将使用驱动翼型产生，能够产生频率、幅度和方向独立可变的有组织的非稳定流动，使我们能够准确地描绘潜在有益的环境流动。加速测量结果将与空气动力学和新陈代谢结果进行比较，以研究在广泛的飞行速度和气流模式下，使用加速测量作为飞行能量消耗的替代指标的可行性。这项研究的更广泛影响集中在本科生研究体验计划，根据该计划，国家招收的生物和工程或物理本科生将接受跨学科研究和合作培训，同时他们将协助主要项目目标，并与团队其他成员协商，设计和执行自己的子项目。该奖项由生物IOS-生理机制和生物力学计划和ENG-CBET-流体动力学计划共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Recent field studies of flight mechanics in birds of several types and sizes have revealed more use of environmental energy (e.g. gusts, wakes and updrafts) to power flight than was previously believed to be the case. However, because the detailed studies of the aerodynamics, flight costs and flight mechanics of birds have been carried out in wind tunnels with smooth, steady air flow, little is known about how birds take advantage of unsteady flow patterns. In this project the researchers will fill this gap in understanding by measuring the energetic cost of flight, the aerodynamics, and the flapping motion of birds in a wind tunnel, comparing smooth flow conditions to 4 different unsteady flow cases. This study will also test the use of body-mounted accelerometers to serve as a proxy measure of the energetic cost of flight over the same wide range of flow conditions, enabling more accurate field studies. This research will add to basic understanding of aerodynamics in unsteady flows and the ecology and evolution of small birds. Pursuing this project requires an interdisciplinary combination of biology and engineering. To further the educational goals of this project, it includes a Research Experience for Undergraduates component. In this sub-program, Biology and Engineering undergraduates from around the nation apply for a summer research fellowship to work on the project. Selected students will assist with the main project and pursue a sub-project of their own design with the assistance of the rest of the project team.In this project the PI and Co-PIs will apply state-of-the-art metabolic aerodynamic and accelerometry measurements to understand the energetic costs or benefits for interactions between birds and potentially beneficial flow structures, along with the underlying aerodynamic mechanisms that give rise to the metabolic outcomes. Flow patterns will be generated using an actuated airfoil capable of producing organized non-steady flows with independently variable frequency, magnitude and direction, allowing us to precisely delineate potentially beneficial environmental flows. Accelerometry results will be compared to aerodynamic and metabolic results to investigate the feasibility of using accelerometry as a proxy for energy expenditure in flight across a wide range of flight speeds and airflow patterns. Broader impacts from this study focus on a Research Experience for Undergraduates program whereby nationally recruited Biology and Engineering or Physics undergraduates will be trained in interdisciplinary research and collaboration while they assist with the main project goals and, in consultation with the rest of the team, design and execute their own sub-project.This award is co-funded by the BIO-IOS-Physiological Mechanisms and Biomechanics Program and the ENG-CBET-Fluid Dynamics Program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.