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Hydrodynamic advantages of in-line schooling
Mehdi Saadat1,2, Florian Berlinger3, Artan Sheshmani4,5,6
1Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, United States of America.
Bioinspiration & Biomimetics
|January 29, 2021
Summary
Fish swimming in groups gain energy savings through enhanced thrust, not just reduced drag. This discovery enables bioinspired designs for more efficient underwater propulsion systems.
Area of Science:
- Fluid dynamics
- Biomechanics
- Robotics
Background:
- Fish schooling offers energetic benefits, with followers saving energy.
- Existing theories like drafting don't fully explain in-line schooling advantages.
Purpose of the Study:
- To investigate the hydrodynamic mechanisms behind energy savings in in-line fish schooling.
- To propose an alternative hypothesis based on propulsive thrust enhancement.
Main Methods:
- Utilized an idealized model of in-line pitching foils to simulate fish schools.
- Analyzed the fluid dynamics of the undulatory jet interaction between foils.
Main Results:
- Identified two key mechanisms: leading-edge suction on the trailer and added-mass push on the leader.
- Demonstrated potential power savings up to 70% in compact schooling arrangements.
- Achieved up to 56% power savings in a bioinspired autonomous swimming robot.
Conclusions:
- The study refutes the drafting hypothesis for in-line schooling.
- Propulsive thrust enhancement is a primary driver of energetic benefits in schooling fish.
- Findings facilitate the development of highly efficient bioinspired propulsion systems.
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