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We extend recent results on 2D (wall to wall) flat plates executing various pitching motions, to rectangular and elliptical (Zimmerman planform) plates of aspect ratio 2, at reduced frequency up to 2.0. Motions include, broadly, two kinds. The first is a smoothed linear pitch from 0° to 90° incidence angle, with constant freestream and with relative free-stream linearly decelerating to zero towards motion completion, where the operative question is how the motion dynamics mediates stall. The second is a linear pitch ramp-hold-return maneuver, where one is interested not only in the dynamic stall response, but also return from stall. Surveying a range of pivot point locations and pitch rates, we compare the development of leading edge vortices, tip vortices and trailing edge vortices, with trends in lift coefficient and drag coefficient history. For highfrequency motions, the lift peak no longer closely correlates with the maximum strength of the leading edge vortex, or with its shedding. Instead, vortex formation and shedding can lag both the motion and the lift peak. Tip vortices evolve more slowly than leading edge vortices, in the sense that a tip vortex remains coherent and nearly attached to the wingtip until well past leading edge vortex saturation and shedding. Qualitatively the low aspect ratio plates behave as does the 2D plate; for example, taking the pitch pivot point further aft, results in both lower lift and drag peaks; and taking a very high reduced frequency of pitch, results in initial lift transients akin to those with outright zero free stream flow. Broadly, the lift history of the low aspect ratio plates has lower slope than for the 2D plate, but not with the same proportionality that holds for the steady case. However, classical scaling relations for lift as a function of reduced frequency hold nearly as well for the low aspect ratio plates, as they do for the 2D plate.

Flowfield Evolution vs. Lift Coefficient History for Rapidly-Pitching Low Aspect Ratio Plates