摘要：AbstractIn this paper, we make experimental observations of the perturbed Rayleigh-Bénard convection to detect the Lagrangian coherent structures (LCSs), which correspond to the invariant manifolds of time-dependent systems and also to investigate the associated fluid transports by numerically integrating the two-dimensional velocity field obtained by Particle Image Velocimetry (PIV). We show the chaotic fluid transports that appear in the system, though some particles are transported almost periodically with time period T or 3T, where T = 17.3 s is the period of the perturbation. We finally propose a novel perturbed Hamiltonian system that enables to recover qualitatively global behaviors observed in experimental results and we also explore the periodic fluid transport that appear in the system.
