Mapping spatial patterns to energetic benefits in groups of flow-coupled swimmers

Area of Science:

• Fluid dynamics
• Biomechanics
• Animal behavior

Background:

• Coordinated animal movement through fluids often reduces individual locomotion costs.
• The relationship between spatial patterns in animal groups and individual energetic benefits is not fully understood.

Purpose of the Study:

• To investigate the energetic benefits and spatial dynamics of cohesive formations in groups of fish.
• To understand how flow coupling influences the cost of locomotion for individuals in different group arrangements.

Main Methods:

• Modeling fish as flapping foils in pairwise and larger group formations.
• Analyzing flow coupling and energy distribution in side-by-side and inline arrangements.
• Developing diagnostic tools to identify hydrodynamic benefit zones.

Main Results:

• Side-by-side formations equalize energy costs, benefiting in-phase swimmers but not antiphase.
• Inline formations offer benefits to trailing swimmers up to a critical group size, beyond which cohesion and benefits are lost.
• Identified specific locations in the wake of swimmers offering hydrodynamic advantages.

Conclusions:

• Flow physics dictates energetic savings and losses within animal groups.
• Spatial arrangements and flapping synchronization critically influence locomotion costs and group cohesion.
• Findings link hydrodynamic resources to social behaviors like cooperation and resource competition.