Passing the Wake: Using Multiple Fins to Shape Forces for Swimming

Area of Science:

• Biomechanics
• Robotics
• Fluid Dynamics

Background:

• Fish exhibit superior underwater maneuverability compared to current unmanned underwater vehicles (UUVs).
• Locomotion in fish involves complex, coordinated movements of multiple fins and body, varying with species and task.
• Fin interactions and their timing significantly influence propulsive forces and fluid dynamics.

Purpose of the Study:

• To investigate how fin phase and geometric relationships affect propulsive forces in multifin systems.
• To understand the fluid dynamics underlying force generation in interacting fins.
• To explore potential applications for enhancing robotic swimming capabilities.

Main Methods:

• Utilized a multifin biorobotic experimental platform.
• Employed two-dimensional computational fluid dynamics (CFD) simulations.
• Analyzed the effects of fin phase and geometric configurations on generated forces.

Main Results:

• Forces from interacting fins differ substantially from the sum of forces from non-interacting fins.
• Manipulating fin phase and location significantly alters the magnitude and shape of propulsive forces.
• Time-varying wakes from dorsal and anal fins impact downstream flow and affect caudal fin performance.

Conclusions:

• Interactions between fins are crucial for generating effective propulsive forces.
• Controlling fin phase and position offers a powerful method for modulating swimming forces in robotic systems.
• Findings provide insights for designing more agile and efficient biomimetic underwater vehicles.