Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published November 7, 2012 | Published
Journal Article Open

Biomimetic and Live Medusae Reveal the Mechanistic Advantages of a Flexible Bell Margin


Flexible bell margins are characteristic components of rowing medusan morphologies and are expected to contribute towards their high propulsive efficiency. However, the mechanistic basis of thrust augmentation by flexible propulsors remained unresolved, so the impact of bell margin flexibility on medusan swimming has also remained unresolved. We used biomimetic robotic jellyfish vehicles to elucidate that propulsive thrust enhancement by flexible medusan bell margins relies upon fluid dynamic interactions between entrained flows at the inflexion point of the exumbrella and flows expelled from under the bell. Coalescence of flows from these two regions resulted in enhanced fluid circulation and, therefore, thrust augmentation for flexible margins of both medusan vehicles and living medusae. Using particle image velocimetry (PIV) data we estimated pressure fields to demonstrate a mechanistic basis of enhanced flows associated with the flexible bell margin. Performance of vehicles with flexible margins was further enhanced by vortex interactions that occur during bell expansion. Hydrodynamic and performance similarities between robotic vehicles and live animals demonstrated that the propulsive advantages of flexible margins found in nature can be emulated by human-engineered propulsors. Although medusae are simple animal models for description of this process, these results may contribute towards understanding the performance of flexible margins among other animal lineages.

Additional Information

© 2012 Colin et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Received July 18, 2012; Accepted October 8, 2012; Published November 7, 2012. This work was supported by an ONR MURI award to SP (N000140810654) and National Science Foundation grant OCE 0623508 to JHC, SPC, JOD. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We wish to thank Colin Smith for his help videoing the robotic jellyfish and Richard Satterlie for insightful conversations about the neuromuscular biology of jellyfish. We thank the New England Aquarium for their contributions of cultured medusae. Author Contributions: Conceived and designed the experiments: SPC JHC AV SP JBB. Performed the experiments: SPC JHC AV BJG. Analyzed the data: SPC JHC JOD BJG. Contributed reagents/materials/analysis tools: AV SP. Wrote the paper: SPC JHC.

Attached Files

Published - journal.pone.0048909.pdf


Files (1.4 MB)
Name Size Download all
1.4 MB Preview Download

Additional details

August 19, 2023
October 23, 2023