A Computational Study on the Dynamic Stall of a Flapping Airfoil

Abstract

The dynamic stall boundaries of a NACA 0012 airfoil oscillating in either the pure plunge mode or in the combined pitch and plunge mode is computed using a thin-layer Navier-Stokes solver. Unsteady flowfields are computed at the free-stream Mach number of 0.3, the Reynolds number of 1 • 106, and the Baldwin-Lomax turbulence model is employed. It is found that the pure plunge oscillation leads to dynamic stall as soon as the non-dimensional plunge velocity exceeds the approximate value of 0.35. In addition, the power extraction capability of the airfoil operating in the wingmill mode is studied by computing the dynamic stall boundary for a combined pitch and plunge motion at the reduced frequency values of 0.1, 0.25 and 0.5.