Biomimetic shark skin: design, fabrication and hydrodynamic function.

Area of Science:

• Biomimetics
• Fluid Dynamics
• Materials Science

Background:

• Shark skin's surface roughness creates complex hydrodynamic effects, crucial for efficient swimming.
• Previous attempts to create flexible biomimetic shark skin for functional studies have been unsuccessful.

Purpose of the Study:

• To design, fabricate, and hydrodynamically test a novel synthetic, flexible shark skin membrane.
• To investigate the impact of biomimetic shark skin structures on swimming performance and energy efficiency.

Main Methods:

• A 3D model of shark skin denticles was created using micro-CT imaging of mako shark skin.
• Thousands of synthetic denticles were 3D printed onto flexible membranes in a controlled pattern.
• The biomimetic skin was tested using a robotic flapping device in water, comparing performance to a smooth control.

Main Results:

• The 3D printed shark skin demonstrated increased swimming speed (6.6%) and reduced energy cost-of-transport (5.9%) under specific motion conditions.
• A stronger leading-edge vortex was generated by the synthetic skin compared to the smooth control, potentially explaining speed increases.
• The fabricated skin allowed for dynamic movement testing at self-propelled swimming speeds.

Conclusions:

• This study presents the first successful fabrication of flexible biomimetic shark skin for hydrodynamic studies.
• The findings highlight the potential of synthetic shark skin to improve aquatic locomotion efficiency.
• This fabrication method allows for future manipulation of surface roughness parameters and investigation of diverse shark skin morphologies.