Fabrication and Drag Reduction Performance of Bionic Surfaces Featuring Staggered Shield Scale Structures.

Area of Science:

• Biomimetics and Surface Engineering
• Fluid Dynamics and Hydrodynamics

Background:

• Shark skin's unique placoid scales inspire novel drag reduction strategies.
• Understanding the fluid dynamics of natural surfaces is key to developing efficient technologies.

Purpose of the Study:

• To investigate the drag reduction mechanism of shark skin placoid scales.
• To design and fabricate a biomimetic surface for high-efficiency drag reduction.

Main Methods:

• Fabrication of biomimetic shark skin using laser etching and polydimethylsiloxane (PDMS) replication.
• Sedimentation experiments to measure drag reduction rates.
• Computational fluid dynamics (CFD) simulations to analyze near-wall flow characteristics.

Main Results:

• The biomimetic surface achieved a drag reduction rate of 5.65% in sedimentation experiments.
• CFD simulations showed drag reduction is due to regulated near-wall laminar flow, forming low-velocity layers and recirculation zones.
• Staggered grooves improved pressure distribution, reducing pressure drag, with simulated drag reduction at 5.08%.

Conclusions:

• The biomimetic placoid structure effectively reduces fluid drag.
• The study validates the feasibility and effectiveness of bio-inspired surfaces for drag reduction applications.