title: Clustering of salt fingers in double-diffusive convection leads to staircaselike stratification.
abstract: We report on high-resolution, three-dimensional, high Rayleigh number, and low density ratio numerical simulations of fingering convection. We observe a previously unreported phenomenon of self-organization of fingers that cluster together to form larger-scale coherent structures. The flow ultimately forms density staircases, alternating well-mixed regions with fingering convective zones. We give evidence that the mechanical mixing induced by the clusters forms the staircases with a mechanism analogous to staircase formation in a stably stratified, nonconvective, stirred fluid.
authors.affiliation: Dipartimento di Matematica e Fisica Ennio De Giorgi, Università del Salento, 73100 Lecce, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Paparella
authors.forename: Jost
authors.initials: J
authors.lastname: von Hardenberg