Collaborative Research: Optimizing flexible swimmers -- from jellyfish to engineered propulsors

0754493/0754922 Dabiri和Freund该项目将联合收割机新的实验和计算工具，在生物启发推进器的设计和优化。对于工程技术，成功地复制所观察到的生物系统的性能，需要了解推进器的灵活性和非线性弹性，在生物推进系统中无处不在的特性的动态作用。为了实现这一目标，PI将研究水母游泳作为生物推进的模型系统。这些动物是一个引人注目的模型，因为它们代表了生物推进器的最简单的例子之一，但表现出耦合的流体-结构相互作用，大变形和非线性弹性。此外，最近编制的600多种水母的形态数据库可用于比较工程设计优化的结果与自然界中发现的解决方案。该项目的目标是通过最近开发的一个完全耦合的，二维的，大变形，流体结构求解器，在一个新的范式内的功能：材料特性和驱动力指定，而不是推进器运动学或流入边界条件。数值方法最终将扩展到轴对称和三维配置。实验工具将为数值模型的验证和改进、设计优化的初始输入以及最佳解决方案的评估提供重要的新数据。数字粒子图像测速（DPIV）测量将同时和顺序收集在自由游动的水母所产生的流场的多个平面。这些数据将使用传统的速度和涡度度量以及使用新的拉格朗日工具从动力系统进行评估。该合作将使实验和模拟的共同设计能够最大限度地发挥其相互效用，以了解生物推进和优化生物启发的工程设计。最近在加州理工学院开发了一门关于“生物推进”的课程，由一位PI教授，将作为这项研究的教育途径。为了接触到更广泛的受众，伊利诺伊州的研究小组将建立一个用户友好的版本的开发代码用于教学。加州理工学院的调查员还将继续担任加州理工学院新生暑期研究所（FSI）研究计划的协调员，该计划将代表性不足的新生介绍给研究型大学的环境。最后，两个PI将指导本科生和研究生的日常研究活动。

0754493/0754922 Dabiri and Freund This project will combine new experimental and computational tools in the design and optimization of biologically-inspired propulsors. For engineering technology to successfully replicate the observed performance of biological systems requires understanding the dynamical role of propulsor flexibility and nonlinear elasticity, characteristics that are ubiquitous in biological propulsion systems. Toward this aim, the PIs will investigate jellyfish swimming as a model system for biological propulsion in general. These animals are a compelling model because they represent one of the simplest examples of a biological propulsor and yet exhibit coupled fluid-structure interactions, large deformations, and nonlinear elasticity. Furthermore, a recently compiled morphological database of over 600 species of jellyfish is available to compare the results of the engineering design optimization with the solutions found in nature. The project objectives are made possible by the recent development of a fully-coupled, two-dimensional, large-deformation, fluid-structure solver that functions within a novel paradigm: material properties and actuation forces are specified instead of propulsor kinematics or inflow boundary conditions. The numerical method will eventually be extended to axisymmetric and three-dimensional configurations. Experimental tools will provide essential new data for validation and refinement of the numerical model, initial inputs to the design optimization, and evaluation of the optimal solutions. Digital particle image velocimetry (DPIV) measurements will be collected both simultaneously and sequentially in multiple planes of the flow field created by free-swimming jellyfish. These data will be evaluated using traditional velocity and vorticity metrics as well as by using new Lagrangian tools from dynamical systems. The collaboration will enable co-design of the experiments and simulations to maximize their mutual utility for understanding biological propulsion and optimizing biologically-inspired engineering designs. A recently developed course on "Biological Propulsion" at Caltech, taught by one of the PIs, will serve as an educational outlet for this research. In order to reach a broader audience, the Illinois group will set up a user-friendly version of the developed code for use in instruction. The Caltech investigator will also continue in his role as Coordinator of the Freshmen Summer Institute (FSI) Research Program at Caltech, which introduces underrepresented incoming freshman to the environment of a research university. Finally, both PIs will mentor undergraduate and graduate students in the day-to-day research activities.