title: Inverse cascades sustained by the transfer rate of angular momentum in a 3D turbulent flow.
abstract: The existence of energy cascades as signatures of conserved magnitudes is one of the universal characteristics of turbulent flows. In homogeneous 3D turbulence, the energy conservation produces a direct cascade from large to small scales, although in 2D, it produces an inverse cascade pointing towards small wave numbers. In this Letter, we present the first evidence of an inverse cascade in a fully developed 3D experimental turbulent flow where the conserved magnitude is the angular momentum. Two counterrotating flows collide in a central region where very large fluctuations are produced, generating a turbulent drag that transfers the external torque between different fluid layers.
authors.affiliation: Departamento de Física y Matemática Aplicada, University of Navarra, P.O. Box 177, E-31080 Pamplona, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: López-Caballero
authors.affiliation: Departamento de Física y Matemática Aplicada, University of Navarra, P.O. Box 177, E-31080 Pamplona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Burguete