Control of vortex rings for manoeuvrability

Area of Science:

• Fluid dynamics
• Biomechanics
• Animal locomotion

Background:

• Maneuverability is crucial for species survival, with animals exhibiting sophisticated control of fluid dynamics for propulsion.
• Understanding biological propulsion mechanisms, particularly vortex dynamics in aquatic environments, is key for both biological insights and engineering applications.

Purpose of the Study:

• To investigate how jellyfish (Aurelia aurita) modulate vortex rings during turning maneuvers.
• To elucidate the role of bell kinematics and musculature in generating asymmetric thrust for directional control.

Main Methods:

• Utilized volumetric and planar imaging techniques to quantify vortex ring formation and interaction.
• Employed fluorescent actin staining to identify muscle fiber distribution within the jellyfish bell margin.

Main Results:

• Jellyfish distort individual vortex rings during turns to alter force balance, primarily via kinematic modulation of the bell margin.
• A portion of the vortex ring separates from the body during turns, potentially increasing torque.
• Radial muscle fibers are present along the bell margin, providing a mechanism for kinematic control.

Conclusions:

• Jellyfish possess a biological mechanism involving radial muscles to actively alter bell kinematics for non-symmetric thrust generation.
• This study provides new insights into the modulation and control of vorticity for low-speed animal maneuvering, with implications for bio-inspired engineering.