Aerodynamics of Bio-Inspired Airfoils Under Plunging Motion

The effects of various corrugated geometries on the aerodynamic performance of bio-inspired airfoils are investigated under pure plunging motion at a low Reynolds number. Following a comprehensive review of previous studies on corrugated insect-inspired airfoils under gliding, pitching, and flapping motions, the present work addresses their unexplored aerodynamic behavior under plunging motion. Three corrugated cross-sections of the dragonfly Aeshna cyanea, along with their corresponding profiled airfoils, are considered and compared with a flat plate and a NACA0012 airfoil to examine the influence of their geometrical characteristics on aerodynamic forces. The unsteady Reynolds-Averaged Navier–Stokes equations, closed by the k–ω SST-SAS turbulence model, are solved using ANSYS Fluent at α = 0° and a Reynolds number of 7600. Validation against two-dimensional (2D) experimental data for a plunging flat plate shows maximum deviations of 0.9% and 1.9% in the lift and drag coefficients, respectively. The results indicate that the third corrugated airfoil achieves a maximum lift-to-drag ratio that is 27% and 30% higher than those of the flat plate and NACA0012 airfoil, respectively.