Inverse cascade behavior in freely decaying two-dimensional fluid turbulence

• Autores: Mininni, P.D.; Pouquet, A.
• Año de publicación: 2013
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Phys. Rev. E Stat. Nonlinear Soft Matter Phys. 2013;87(3)
• Materia: Experimental studies; Fluid turbulence; Inverse energy cascades; Negative fluxes; Random initial conditions; Source of energy; Spatial resolution; Two-dimensional hydrodynamics; Magnetohydrodynamics; Reynolds number; Two dimensional; Turbulence
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

We present results from an ensemble of 50 runs of two-dimensional hydrodynamic turbulence with spatial resolution of 20482 grid points and from an ensemble of 10 runs with 40962 grid points. All runs in each ensemble have random initial conditions with the same initial integral scale, energy, enstrophy, and Reynolds number. When both ensemble and time averaged, an inverse energy cascade behavior is observed, even in the absence of external mechanical forcing: The energy spectrum at scales larger than the characteristic scale of the flow follows a k-5/3 law, with negative flux, together with a k-3 law at smaller scales, and a positive flux of enstrophy. The source of energy for this behavior comes from the modal energy around the energy-containing scale at t=0. The results shed some light on the connections between decaying and forced turbulence and recent controversies in experimental studies of two-dimensional and magnetohydrodynamic turbulent flows. © 2013 American Physical Society.
Fil:Mininni, P.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.