title: Lagrangian tracers on a surface flow: the role of time correlations.
abstract: Finite time correlations of the velocity in a surface flow are found to be important for the formation of clusters of Lagrangian tracers. The degree of clustering characterized by the Lyapunov spectrum of the flow is numerically shown to be in qualitative agreement with the predictions for the white-in-time compressible Kraichnan flow, but to deviate quantitatively. For intermediate values of compressibility the clustering is surprisingly weakened by time correlations.
authors.affiliation: Dipartimento di Fisica Generale and INFM, Università di Torino, Via Pietro Giuria 1, I-10125 Torino, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Boffetta
authors.forename: Jahanshah
authors.initials: J
authors.lastname: Davoudi
authors.forename: Bruno
authors.initials: B
authors.lastname: Eckhardt
authors.forename: Jörg
authors.initials: J
authors.lastname: Schumacher