6,049 research outputs found

    Energy Spectrum of Quasi-Geostrophic Turbulence

    Full text link
    We consider the energy spectrum of a quasi-geostrophic model of forced, rotating turbulent flow. We provide a rigorous a priori bound E(k) <= Ck^{-2} valid for wave numbers that are smaller than a wave number associated to the forcing injection scale. This upper bound separates this spectrum from the Kolmogorov-Kraichnan k^{-{5/3}} energy spectrum that is expected in a two-dimensional Navier-Stokes inverse cascade. Our bound provides theoretical support for the k^{-2} spectrum observed in recent experiments

    Algebraic constructions in the category of vector bundles

    Full text link
    The category of generalized Lie algebroids is presented. We obtain an exterior differential calculus for generalized Lie algebroids. In particular, we obtain similar results with the classical and modern results for Lie algebroids. So, a new result of Maurer-Cartan type is presented. Supposing that any vector subbundle of the pullback vector bundle of a generalized Lie algebroid is called interior differential system (IDS) for that generalized Lie algebroid, a theorem of Cartan type is obtained. Extending the classical notion of exterior differential system (EDS) to generalized Lie algebroids, a theorem of Cartan type is obtained. Using the theory of linear connections of Ehresmann type presented in the paper [1], the identities of Cartan and Bianchi type are presented.Comment: 29 page

    Mechanical Systems in the Generalized Lie Algebroids Framework

    Full text link
    \emph{Mechanical systems} called by use, \emph{mechanical}(ρ,η)\left(\rho ,\eta\right) \emph{-systems, Lagrange mechanical}(ρ,η)\left(\rho ,\eta \right) \emph{-systems} or \emph{Finsler mechanical}(ρ,η)\left(\rho ,\eta \right) \emph{-systems} are presented. The canonical (ρ,η)\left(\rho ,\eta \right) \emph{-}semi(spray) associated to a mechanical (ρ,η)\left(\rho ,\eta \right) -system is obtained. New and important results are obtained in the particular case of Lie algebroids. The Lagrange mechanical (ρ,η)(\rho ,\eta)% -systems are the spaces necessary to develop a new Lagrangian formalism. We obtain the (ρ,η)(\rho ,\eta)-semispray associated to a regular Lagrangian LL and external force FeF_{e} and we derive the equations of Euler-Lagrange type. So, a new solution for the Weinstein's Problem in the general framework of generalized Lie algebroids is presented.Comment: 43 pages International journal of Geometric Methods in Modern Physics, 2013. arXiv admin note: substantial text overlap with arXiv:1108.2844, arXiv:1007.1541, arXiv:1109.1242, arXiv:1101.0960, arXiv:1108.505
    corecore