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的鸟类飞行力学的实地研究表明，与以前认为的情况相比，更多地使用环境能量（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是在具有平稳、稳定气流的风洞中进行的，因此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扑翼运动来填补这一理解上的空白，将平稳流动条件与4种不同的非定常流动情况进行比较。这项研究还将测试使用安装在机身上的加速度计，作为在同样广泛的流动条件下飞行的能量成本的替代测量，从而能够进行更准确的实地研究。这项研究将增加对非定常流中空气动力学和小型鸟类生态学和进化的基本了解。追求这个项目需要生物学和工程学的跨学科结合。为了进一步实现该项目的教育目标，它包括本科生的研究经验。在这个子项目中，来自全国各地的生物学和工程学本科生申请暑期研究奖学金，从事该项目。被选中的学生将协助完成主项目，并在项目团队其他成员的协助下完成自己设计的子项目。在这个项目中，PI和Co-PI将应用最先进的代谢空气动力学和加速度测量，以了解鸟类与潜在有益的流动结构之间相互作用的能量成本或收益，沿着产生代谢结果的潜在空气动力学机制。流型将使用能够产生有组织的非定常流与独立可变的频率，幅度和方向，使我们能够精确地描绘潜在的有益的环境流的驱动翼型。加速度测量结果将与空气动力学和代谢结果进行比较，以研究在广泛的飞行速度和气流模式下使用加速度测量作为飞行中能量消耗的代理的可行性。这项研究的更广泛的影响集中在本科生计划的研究经验，全国招募的生物学和工程或物理学本科生将接受跨学科研究和合作的培训，同时他们协助实现主要项目目标，并与团队的其他成员协商，设计和执行自己的子项目。该奖项由BIO-IOS-生理机制和生物力学计划和ENG-CBET-流体动力学计划。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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.