Numerical Study into the Spanwise Effects for the Three-Dimensional Unsteady Flow over a Bio-Inspired Corrugated...

Area of Science:

• Fluid dynamics
• Aerodynamics
• Biomimetics

Background:

• Insect wings feature corrugations that influence aerodynamics.
• Understanding flow behavior at low Reynolds numbers (Re) is crucial for biomimetic design.
• Previous studies lack comprehensive analysis of spanwise effects on corrugated wings.

Purpose of the Study:

• To computationally analyze the three-dimensional (3D) airflow over a corrugated wing.
• To investigate flow behavior across a range of Reynolds numbers (10–10,000) and angles of attack (-5° to 20°).
• To determine the influence of spanwise effects and identify flow regime transitions.

Main Methods:

• Employed a 3D computational fluid dynamics (CFD) analysis.
• Ensured numerical reliability through expanded verification and validation.
• Examined flow characteristics including steady flow, recirculation zones, and vortex shedding.

Main Results:

• At low Re, flow is steady and 2D with recirculation zones.
• Increasing Re or angle of attack leads to periodic vortex shedding and 3D structures.
• Corrugations do not enhance lift-to-drag ratio in steady gliding but delay separation in transitional regimes.
• Periodic shedding at Re=10,000 indicates bluff body-like behavior.

Conclusions:

• Corrugated wings exhibit complex flow dynamics, transitioning from 2D to 3D behavior with increasing Re and angle of attack.
• Spanwise flow structures are significant, challenging 2D assumptions in certain flow regimes.
• Findings provide insights into insect wing aerodynamics and inform biomimetic designs for enhanced flight performance.