Flexible swimmers: reverse engineering a jellyfish

CBET-0931413 Dabiri，John O.该奖项是根据2009年美国复苏和再投资法案(公法第111-5条)资助的。该项目将在柔性推进器的设计中结合实验和计算，即对水母进行逆向工程。为了成功地复制观察到的水母的游泳性能，重要的是首先了解推进器灵活性和非线性弹性的动力学作用，这是生物推进系统中普遍存在的特征。水母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，但表现出流固耦合、大变形和非线性弹性。因此，从这项研究中提取的设计原则可能适用于高等生物体和工程推进系统。此外，最近汇编的600多种水母的形态数据库可用于将工程设计优化的结果与自然界中发现的解决方案进行比较。实验工具将为数值模型的验证和改进提供必要的新数据，为设计优化提供初始输入，并评估最优解。特别是，已经开发了新的实验方案来量化活水母的肌肉结构和激活动力学。数字粒子图像测速仪(DPIV)将在自由游动的水母形成的流场的多个平面上同时和顺序地采集测量数据。继续与UIUC的乔恩·弗洛伊德合作，有望为这项研究增加计算方面的影响。在本项目期间制定的方法将通过网上教程传播，就像各私人投资机构以前所做的那样。这个项目的跨学科性质将被用来让来自工程学和生物学背景的学生接触研究方法。加州理工学院最近开发的一门关于生物推进的课程将作为这项研究的教育渠道。PI还将继续担任加州理工大学新生暑期学院(FSI)研究项目的协调员，该项目向未被充分代表的新生介绍研究型大学的环境。最后，两位PI都将在日常研究活动中指导本科生和研究生。

CBET - 0931413 Dabiri, John O.This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This project will combine experiments and computations in the design of flexible propulsors, i.e., to reverse engineer a jellyfish. To successfully replicate the observed swimming performance of jellyfish, it is important to first understand the dynamical role of propulsor flexibility and nonlinear elasticity, characteristics that are ubiquitous in biological propulsion systems. Jellyfish 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. Hence, the design principles extracted from this study can potentially be applied to higher organisms and engineered propulsion systems. 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. 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. In particular, new experimental protocols have been developed to quantify the muscle architecture and activation dynamics of live jellyfish. 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. Continuing collaboration with Jon Freund at UIUC is expected to add a computational aspect to this study. The methods developed during this project will be disseminated via web-based tutorials, as has been done previously by the PIs. The interdisciplinary nature of this project will be leveraged to expose students from engineering and biology backgrounds to research methods. A recently developed course on 'Biological Propulsion' at Caltech will serve as an educational outlet for this research. The PI will also continue in his role as Coordinator of the Freshmen Summer Institute (FSI) Research Program at Caltech that 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.