title: Lagrangian coherent structures and the smallest finite-time Lyapunov exponent.
abstract: We point out that local minimizing curves, or troughs, of the smallest finite-time Lyapunov exponent (FTLE) field computed over a time interval [t(0), t] and graphed over trajectory positions at time t mark attracting Lagrangian coherent structures (LCSs) at t. For two-dimensional area-preserving flows, we conclude that computing the largest forward-time FTLE field by itself is sufficient for locating both repelling LCSs at t(0) and attracting LCSs at t. We illustrate our results on analytic examples, as well as on a two-dimensional experimental velocity field measured near a swimming jellyfish.
authors: Department of Mechanical Engineering, McGill University, 817 Sherbrooke Ave. West, Montreal, Quebec H3A 2K6, Canada.
authors: George
authors: G
authors: Haller
authors: Themistoklis
authors: T
authors: Sapsis