title: Complex dynamical states in binary mixture convection with weak negative Soret coupling.
abstract: Binary convection in large-aspect-ratio annular containers heated from below is studied numerically for a water-ethanol mixture. High-resolution numerical tools based on spectral methods are used to solve the hydrodynamic equations in the two-dimensional approximation. The weakly nonlinear states arising very close to the onset of convection, the strongly nonlinear bursts of amplitude that precede the small-amplitude states, and the dispersive chaotic states encountered further above onset in experiments for mixtures with a weak negative Soret coupling are analyzed in detail in extended domains of aspect ratio 80. Steady localized states surrounded either by quiescent fluid or by small-amplitude waves are also obtained, and the role they play in the dynamics is elucidated.
authors.affiliation: Departament de Física Aplicada, Universitat Politècnica de Catalunya, Mòdul B4, 08034 Barcelona, Spain. arantxa@fa.upc.edu
authors.forename: Arantxa
authors.initials: A
authors.lastname: Alonso
authors.forename: Oriol
authors.initials: O
authors.lastname: Batiste
authors.forename: Alvaro
authors.initials: A
authors.lastname: Meseguer
authors.forename: Isabel
authors.initials: I
authors.lastname: Mercader