Exploring the swimming performance and the physical mechanisms ofTomopterislocomotion

Area of Science:

• Marine Biology
• Biomechanics
• Fluid Dynamics

Background:

• Tomopterids are holopelagic marine invertebrates known for their unique swimming style.
• They exhibit simultaneous use of metachronal paddling and bodily undulation for locomotion.
• The interplay between these two distinct modes of movement has been a subject of interest.

Purpose of the Study:

• To investigate the synergistic mechanisms of simultaneous paddling and undulation in Tomopteris for effective swimming.
• To explore how variations in parapodia length, paddling amplitude, and undulatory amplitude influence swimming performance.
• To understand the energetic costs associated with different locomotion strategies.

Main Methods:

• Development of a self-propelled, fluid-structure interaction model of an idealized Tomopteris.
• Utilizing a machine learning framework based on polynomial chaos expansions to explore a 3D mechanospace.
• Systematic analysis of swimming performance across a range of parapodia lengths, paddling amplitudes, and undulatory amplitudes.

Main Results:

• Undulatory amplitude had a minimal direct impact on forward (FWD) swimming speeds.
• Bodily undulation was found to mitigate increased costs of transport associated with larger paddling amplitudes or longer parapodia.
• The study identified complex interactions between paddling and undulation parameters affecting overall swimming efficiency.

Conclusions:

• Tomopteris locomotion is a result of a complex synergy between metachronal paddling and bodily undulation.
• Bodily undulation plays a crucial role in optimizing energetic efficiency, particularly under conditions of high paddling effort or elongated parapodia.
• The findings provide insights into the biomechanical principles governing efficient locomotion in marine invertebrates.