Flexible swimmers: reverse engineering a jellyfish

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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.