Numerical Investigation on Drag Reduction Mechanisms of Biomimetic Microstructure Surfaces.

Area of Science:

• Fluid dynamics
• Surface science
• Biomimetics

Background:

• Drag reduction is crucial for marine and aerospace efficiency.
• Biomimetic microstructured surfaces offer a passive drag reduction method.
• Understanding microstructure geometry and dimensions is key to optimizing performance.

Purpose of the Study:

• To investigate drag reduction performance of different groove-type microstructures.
• To optimize the geometry and dimensions of these microstructures.
• To elucidate the underlying mechanisms of drag reduction.

Main Methods:

• Computational fluid dynamics (CFD) simulations were used.
• The shear-stress-transport (SST k-ω) turbulence model was employed.
• Vortex identification utilized the third-generation Ω criterion.

Main Results:

• Blade-groove surfaces achieved the highest drag reduction (18.2%).
• V-groove (16.5%) and arc-groove (14.7%) showed significant, but lower, drag reduction.
• Optimal blade-groove aspect ratios (h+/s+ ≥ 0.75) maintain vortex isolation layers for effective drag reduction.

Conclusions:

• Blade-groove microstructures are most effective for drag reduction.
• Stable near-wall microvortices are the primary mechanism for drag reduction.
• A design framework for biomimetic surfaces combines geometry selection and dimensional optimization.