Modeling how shark and dolphin skin patterns control transitional wall-turbulence vorticity patterns using...

Area of Science:

• Fluid dynamics
• Biophysics
• Computational biology

Background:

• Biological systems like seashells and zebrafish exhibit surface pigmentation patterns formed by reaction-diffusion (RD) mechanisms.
• Fast-swimming marine animals such as sharks and dolphins possess distinct skin patterns that interact with wall turbulence, crucial for drag and noise reduction.

Purpose of the Study:

• To develop a nonlinear spatiotemporal analytical model explaining the control of flow by proud skin patterns in sharks and dolphins.
• To investigate the underlying mechanisms of adaptation in marine animal skin for fluid environment interaction.

Main Methods:

• Developed a minimal self-regulation model for wall turbulence regeneration in the transitional regime, analogous to RD mechanisms.
• Utilized a laterally coupled, diffusive model restricted to pre-breakdown durations and a plane near the wall.
• Investigated the effect of skin organization as a spatiotemporal template of olivo-cerebellar phase reset on vorticity disorganization.

Main Results:

• The model successfully reproduces experimentally observed spatiotemporal organizations of vorticity in transitional and low Reynolds number turbulent flows.
• Demonstrated that skin organization can delay the onset of vorticity disorganization.
• Highlighted commonalities between the adaptation mechanisms of sharks and dolphins to their fluid environments.

Conclusions:

• The proposed model provides a framework for understanding the interaction between biological surfaces and turbulent flow.
• Findings suggest that proud skin patterns play a role in managing fluid dynamics, offering potential for biomimetic applications.
• The study underscores the shared principles of adaptation in marine animal skin for navigating fluid environments.