Control of Aeroelastic Structures via Prescribed Upstream Aerodynamic Disturbances

这笔赠款将通过对流体-结构相互作用的科学理解来促进国家繁荣和安全，这将促进空气动力学、结构动力学和振动控制领域的发展，有利于未来的高效飞机，延长游泳或飞行机器人的耐力，增强风力和水动力发电，以及保护桥梁和管道等基础设施免受风和水流的疲劳破坏。该奖项支持通过从上游扰动发生器引入规定的流动扰动来修改和控制流体-结构相互作用的基础研究。根据不同的应用，可能需要抑制颤振不稳定性或减弱振荡(如在飞机机翼或涡轮叶片中)，增加振荡的幅度(如在振荡流动能量收集器中)，或重塑振荡以有益地影响流体结构的能量传递(如在一群游泳或飞行机器人中同步以最大限度地减少能源消耗)。这里研究的方法将使这些不同的行为中的任何一个都可以按需生成。多学科的方法，以及在中学到博士水平的教育活动，将有助于扩大代表不足的群体参与研究并对工程教育产生积极影响。该项目的目标是通过规定与目标气动弹性翼相互作用的气动扰动，根据需要创建、控制和修改独特的气动弹性系统行为，包括平衡稳定/失稳或极限环振荡幅度增加/减少。该项目旨在了解、模拟和制定气动弹性机翼受到对流涡流等典型流动扰动影响的控制方法。第一个目标是了解和绘制来流扰动与机翼上的非定常气动力和力矩之间的时空关系，使用定制的离散涡流方法和外部流动扰动模型(LDVM-扰动)和风洞实验进行验证。第二个目标是确定来流扰动拓扑、强度、频率含量和相位对气动弹性机翼稳定性和非线性振动行为的影响。这将在仿真中通过将LDVM-扰动模型与气动弹性结构动力学模型耦合来研究，并在验证实验中通过测量激励扰动发生器下游气动弹性翼段的响应来研究。第三个目标是创建一系列前馈系统倒置，以确定所需的扰动发生器运动，以在下游气动弹性机翼中产生所需的响应。该结果将用于展示风洞实验中气动弹性稳定性和振荡现象的开环控制。这一奖项反映了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。

This grant will advance the national prosperity and security through a scientific understanding of fluid-structure interactions that will advance the fields of aerodynamics, structural dynamics, and vibration control favorable for future high-efficiency aircraft, extended endurance in swarms of swimming or flying robots, enhanced wind and hydrokinetic energy generation, and protection of infrastructure like bridges and pipelines from fatigue damage due to wind and water flows. This award supports fundamental research on modifying and controlling fluid-structure interactions by way of introducing prescribed flow disturbances from an upstream disturbance generator. Depending on the application, it may be desirable to suppress a flutter instability or attenuate oscillations (as in an aircraft wing or turbine blade), increase the amplitude of oscillations (as in an oscillating flow energy harvester), or reshape an oscillation to beneficially affect fluid-structure energy transfer (as in a swarm of swimming or flying robots synchronizing to minimize energy consumption). The approach studied here will enable any of these distinct behaviors to be generated on-demand. The multi-disciplinary approach, and the education activities at the middle school through doctoral levels, will help broaden the participation of underrepresented groups in research and positively impact engineering education.The objective of this project is to enable distinct aeroelastic system behaviors including equilibrium stabilization / destabilization or limit cycle oscillation amplitude increase / decrease to be created, controlled, and modified on-demand by prescribing aerodynamic disturbances that interact with a target aeroelastic wing. The project aims to understand, model, and formulate control approaches for aeroelastic wings being affected by canonical flow disturbances such as convecting vortices. The first goal is to understand and map the spatiotemporal relationships between incoming flow disturbances and the unsteady aerodynamic forces and moments on a wing using a custom discrete vortex method with a model for external flow disturbances (LDVM-Disturbance) and wind tunnel experiments for validation. A second goal is to establish the effects of incoming flow disturbance topology, strength, frequency content, and phasing on the stability and nonlinear oscillation behavior of an aeroelastic wing. This will be investigated in simulation by coupling the LDVM-Disturbance model with an aeroelastic structural dynamics model, and in validation experiments by measuring the response of an aeroelastic wing section downstream of an actuated disturbance generator. A third goal is to create a sequence of feed-forward system inversions that allows required disturbance generator motions to be determined to produce desired responses in the downstream aeroelastic wing. The results will be used to demonstrate open-loop control of aeroelastic stability and oscillation phenomena in wind tunnel experiments.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.