This video shows the Finite Time Lyapunov Exponent (FTLE) extracted from grouped fluid particle tracers in backward time over a NACA 65(1)-412 airfoil in 3D. Ridges in the backward FTLE field identify attractors in the flow and are candidates for Lagrangian Coherent Structures.
Three cases are shown: the flow at a chord-based Reynolds number of 20,000 and angles of attack of four and ten degrees and the flow at a Reynolds number of 50,000 at four degrees.
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