Shark skin inspired low-drag microstructured surfaces in closed channel flow

Area of Science:

• Biomimetics and Fluid Dynamics
• Surface Microstructure Engineering

Background:

• Nature-inspired designs offer innovative engineering solutions.
• Shark skin's riblet structure minimizes drag, with applications in fluid dynamics.
• Internal flow effects of riblets are less understood than external flow.

Purpose of the Study:

• To investigate the drag-reducing effects of microstructured riblets in closed channel internal flow.
• To examine dimensional aspects of riblets, including geometry, fluid properties, and channel size.
• To develop conceptual models for riblet-surface vortex interactions.

Main Methods:

• Experimental analysis of riblet-lined rectangular ducts with water and air.
• Systematic variation of parameters: riblet geometry, fluid velocity (laminar/turbulent), viscosity, wettability, and channel size.
• Drag characterization via pressure drop measurements.

Main Results:

• Demonstrated drag reduction in closed channel flow using microstructured riblets.
• Identified key parameters influencing riblet performance, including geometry and flow conditions.
• Observed interactions between fluid vortices and riblet surfaces.

Conclusions:

• Microstructured riblets show potential for drag reduction in internal flow systems.
• Understanding vortex dynamics is crucial for optimizing riblet design.
• Findings contribute to biomimetic engineering and fluid dynamics research.