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Published on: July 19, 2016
Inverse energy cascade in nonlocal helical shell models of turbulence
Massimo De Pietro1, Luca Biferale1, Alexei A Mailybaev2
1Dip. di Fisica and INFN, Università "Tor Vergata," Via della Ricerca Scientifica 1, I-00133 Roma, Italy.
Abstract:
Following the exact decomposition in eigenstates of helicity for the Navier-Stokes equations in Fourier space [F. Waleffe, Phys. Fluids A 4, 350 (1992)], we introduce a modified version of helical shell models for turbulence with nonlocal triadic interactions. By using both an analytical argument and numerical simulation, we show that there exists a class of models, with a specific helical structure, that exhibits a statistically stable inverse energy cascade, in close analogy with that predicted for the Navier-Stokes equations restricted to the same helical interactions. We further support the idea that turbulent energy transfer is the result of a strong entanglement among triads possessing different transfer properties.
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