The optimization and control of flexible propulsors in inviscid fluids

无粘流体中柔性推进器的优化与控制

• 批准号: 0810602
• 负责人: Silas Alben
• 金额: $ 15.2万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-15 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0810602&HistoricalAwards=false
• 关键词: optimization; control; flexible; propulsors; inviscid

The investigator will study five fundamental and interrelated problems dealing with the motions of flapping appendages in inviscid fluids. The first project is a study of the large-amplitude flapping of a rigid plate which sheds vortex sheets into an oncoming fluid. This study will build on the method developed by the proposer for computing the coupled motions of vortex sheets and a flexible flag to consider leading-edge vortices and their interactions with a body and with trailing-edge vortices. The second problem is an improved understanding of how to approximate the spatial complexity of vortex sheets computationally, in settings of vortex-vortex and vortex-body interactions. These approximations will consist of truncations of the multipole expansion of the velocity field induced by vortex sheets. The third project is a study of the optimal flexibility for propulsion, in simple situations modelling two-dimensional motions of fish fins. The work ranges from analysis of linearized solutions to computational solutions of the full system of nonlinear singular integrodifferential equations. The fourth problem considers the mechanics of flexible fins in more detail, through a constrained optimization of a fin ray model. The constraints will be chosen with both the relevant scientific questions and the well-posedness of the optimization problem in mind. The fifth project considers how to control and stabilize the fin ray using our understanding of the mechanics underlying actual fish fins. This effort requires finding optimal target trajectories when the fin stiffness is varied periodically in time, and stabilizing the target trajectories against undesired excitations from body-vortex coupling.The project will develop methods to answer questions of broad biological interest about swimming with fish fins and other flexible locomotory structures. The project will also improve the quantitative understanding of strategies for propulsion which can be readily assimilated into theoretical engineering fields concerning how solids and fluids interact. Applications to propulsion technology include improving the efficiency and maneuverability of submersible vehicles.

研究人员将研究五个基本的和相互关联的问题，在无粘流体中的扑翼附件的运动。第一个项目是研究一个刚性板的大振幅扑动，该刚性板将涡面脱落到迎面而来的流体中。本研究将建立在提议者所开发的用于计算涡面和柔性旗帜的耦合运动的方法的基础上，以考虑前缘涡及其与物体和后缘涡的相互作用。 第二个问题是在涡-涡和涡-体相互作用的情况下，如何通过计算近似涡面的空间复杂性。这些近似将包括由涡面引起的速度场多极展开的截断。第三个项目是研究推进的最佳灵活性，在简单的情况下模拟鱼鳍的二维运动。工作范围从分析的线性化解决方案的计算解决方案的完整系统的非线性奇异积分微分方程。第四个问题考虑更详细的柔性鳍的力学，通过鳍射线模型的约束优化。约束条件的选择将考虑相关的科学问题和优化问题的适定性。 第五个项目考虑如何控制和稳定的鳍射线使用我们的理解实际鱼鳍的力学基础。这项工作需要找到最佳的目标轨迹时，鳍刚度是周期性变化的时间，并稳定的目标轨迹对不希望的激励从身体vortex coupling.The项目将开发的方法来回答广泛的生物学兴趣的问题与鱼鳍和其他灵活的运动结构游泳。该项目还将提高对推进策略的定量理解，这些策略可以很容易地融入有关固体和流体如何相互作用的理论工程领域。推进技术的应用包括提高潜水器的效率和机动性。