title: Large-scale finite-wavelength modulation within turbulent shear flows.
abstract: We show that turbulent "spirals" and "spots" observed in Taylor-Couette and plane Couette flow correspond to a turbulence-intensity modulated finite-wavelength pattern which in every respect fits the phenomenology of coupled noisy Ginzburg-Landau (amplitude) equations with noise. This suggests the existence of a long-wavelength instability of the homogeneous turbulence regime.
authors.affiliation: CEA-Service de Physique de l'Etat Condensé, Centre d'Etudes de Saclay, 91191 Gif-sur-Yvette, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Prigent
authors.forename: Guillaume
authors.initials: G
authors.lastname: Grégoire
authors.forename: Hugues
authors.initials: H
authors.lastname: Chaté
authors.forename: Olivier
authors.initials: O
authors.lastname: Dauchot
authors.forename: Wim
authors.initials: W
authors.lastname: van Saarloos