title: Finite-mode spectral model of homogeneous and isotropic Navier-stokes turbulence: a rapidly depleted energy cascade.
abstract: An eddy-viscous term is added to Navier-Stokes dynamics at wave numbers k greater than the inflection point kc of the energy flux F(log(k)). The eddy viscosity is fixed so that the energy spectrum satisfies E(k) = E(kc) (k/kc)(-3) for k>kc. This resulting forcing induces a rapid depletion of the energy cascade at k>kc. It is observed numerically that the model reproduces turbulence energetics at k< or =kc and statistics of two-point velocity correlations at scales r>lambda (Taylor microscale). Compared to a direct numerical simulation of R(lambda) = 130 an equivalent run with the present model results in a gain of a factor 20 in CPU time.
authors.affiliation: Laboratoire de Physique CNRS, Ecole Normale Supérieure de Lyon, 69364 Lyon Cedex 07, France.
authors.forename: E
authors.initials: E
authors.lastname: Lévêque
authors.forename: C R
authors.initials: CR
authors.lastname: Koudella