Universal Scaling Laws for a Generic Swimmer Model.

Area of Science:

• Fluid dynamics
• Biophysics
• Computational physics

Background:

• Understanding microswimmer propulsion is crucial for fields like biophysics and fluid dynamics.
• Existing models often struggle with accuracy and efficiency across diverse hydrodynamic regimes.
• Simulating collective behaviors of aquatic animals requires computationally feasible models.

Purpose of the Study:

• To introduce a minimal, non-deforming swimmer model using force and torque dipoles.
• To enable accurate and efficient 3D Navier-Stokes calculations for microswimmers.
• To establish universal scaling laws for swimming performance across different Reynolds numbers.

Main Methods:

• Developed a minimal swimmer model based on force and torque dipoles.
• Performed 3D Navier-Stokes simulations for a range of Reynolds numbers.
• Utilized scaling arguments to derive universal laws from numerical data.
• Compared model predictions with experimental data from various microswimmers.

Main Results:

• The model accurately reproduces swimmer propulsion and generates wake vortices, mimicking fish-like flow.
• Numerical exploration yielded universal scaling laws applicable from low to high Reynolds numbers.
• Theoretical scaling laws show excellent agreement with experimental swimming performances across Stokes to turbulent regimes.
• The model's efficiency allows for large-scale simulations of numerous individuals.

Conclusions:

• The minimal swimmer model provides a powerful tool for studying aquatic locomotion and collective behaviors.
• The derived universal scaling laws offer a generalized understanding of swimming efficiency across hydrodynamic regimes.
• This generic model facilitates future research into the complex dynamics of microswimmer assemblies.