Streamwise-Oriented Vortex Interactions with a NACA0012 Wing

摘要

The unsteady interactions of a streamwise-oriented vortex impacting a NACA0012 wing are investigated using high-fidelity numerical simulation. The unsteady modes of interaction and taxonomy of a generic vortex/surface impingement are characterized for two span-wise positions of an incoming vortex, which is imposed analytically upstream of the aspect-ratio-six wing and freely convected in a free stream at a Reynolds number of Re = 2.0 × 10~5. Tip-aligned and inboard-positioned incident vortices are examined and shown to produce rich dynamics through their impingement with the wing. This includes a self-similar flow structure inboard of impingement, whereby earlier separation, reattachment, and abrupt transition of the shear layer are encountered with closer proximity to the incoming vortex. Inboard positioning of the vortex exposes the wingtip to the vortex downwash, thereby reducing the effective angle of attack and resulting in a mostly attached flow outboard of impingement that effectively unloads the wingtip. The core dynamics of the impingement along the leading edge are driven by the development of a spiraling mode instability that alternately deflects the vortex over the suction and pressure sides of the wing. These findings, along with the outboard unloading of the wingtip are consistent with a previous study for flat plates and much lower Reynolds numbers, which may support future numerical studies of these generic vortex/surface interactions at low Reynolds number.