Effects of Inflow Velocity Profile and Rotational Accelerations on LEV Formation for a Revolving Wing

An aspect ratio 10 rectangular wing is revolved in a cylindrical domain at 45 degree angle of incidence, and Reynolds number $Re=O$(1000). Four cases are considered. Case A represents the physical problem in which the approach velocity varies linearly with distance from the axis of rotation, and Coriolis and centripetal accelerations are active in the non-inertial reference frame attached to the wing. Case B implements the same inflow but without rotational accelerations. In cases C and D, the rotational accelerations are the same as A and B, respectively; however, the inflow is uniform along the span. Each case exhibits a strikingly different behavior of the leading-edge vortex (LEV), demonstrating that inflow shear is an important factor governing LEV behavior, in addition to the rotational accelerations. A conical, attached vortex is observed only for case A. Vorticity transport analyses were conducted in chordwise planar control regions, at $z/C=2.0$ (measured from the axis of rotation). In all cases, the leading-edge shear-layer vorticity flux and the diffusive flux from the wing surface provide opposing contributions to the measured circulation; however, they fluctuate significantly for all except case A.