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Session: Intermittency and scaling 2
Session starts: Tuesday 25 August, 15:00
Presentation starts: 15:00
Room: Room H

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Carlos B. da Silva (Instituto Superior Técnico, University of Lisbon)
Ryo Onishi (Center for Earth Information Science and Technology, Japan Agency for Marine-Earth Science and Technology)
Pedro C. Valente (Instituto Superior Técnico, University of Lisbon)

Abstract:
We present data from direct numerical simulations of homogeneous isotropic decaying turbulence showing both the non-equilibrium and the classical dissipation scalings reported in wind-tunnel experiments of both regular and fractal grid-generated turbulence, i.e. Cε ∼ (Re0/Reλ)n with n of order unity and Cε ∼ constant, respectively (Re0 and Reλ are global and local Reynolds numbers). These two dissipation behaviours lead to different power-law decay exponents in both regimes also in accord with the experiments. Finally, we show that in both regimes the maximum non-linear energy cascade flux, Π, reasonably satisfies the classical expectation that Π ∼ K3/2/l.