The instantaneous circulation of vortices shed from an unsteady pitching panel is studied to reveal the formation and shedding processes of leading edge vortices (LEV). The analysis processes a large amount of data from the 2D simulation of a flat plate undergoing a 45° pitch-up maneuver. Large scale lift loss on the panel is shown to correlate with the vortex shedding. The Eulerian Γ_1 and Q criteria, and Lagrangian coherent structures (LCS) analysis including both finite-time Lyapunov exponent (FTLE) and Lagrangian-Averaged Vorticity Deviation (LAVD) are all applied at the center and boundary of the LEV to identify the vortex dynamics. This is compared with a calculation of the circulation. The identified LEV dynamics revealed by multiple vortex criteria matches with the circulation development and lift history in time, indicating a consistent timing of LEV formation, growth, shedding, etc.
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