Scaling laws of two-dimensional incompressible turbulent transport

Abstract

The diffusive transport in two-dimensional incompressible turbulent fields is investigated with the aid of high-quality direct numerical simulations. Three classes of turbulence spectra that are able to capture both short and long-range time-space correlations and oscillating features are employed. We report novel scaling laws that depart from the γ = 7/10 paradigm of percolative exponents and are dependent on the features of turbulence. A simple relation between diffusion in the percolative and frozen regimes is found. The importance of discerning between differential and integral characteristic scales is emphasized.

Neural networks for turbulent transport prediction in a simplified model of tokamak plasmas

“…Consequently, all the trajectories are closed (i.e. trapped particles), and the running diffusion coefficient has an algebraic decay to zero with time [20]; this is due to the fact that the particles remain correlated at any latter time.…”

“…Now we can understand the behavior of the radial diffusion with each of the five parameters (figures 7(a)-(e)). If the perpendicular decorrelation is the one that dominates, then the Kubo number [20] is K ⋆ = Φλ x /λ y . It is known that the turbulent transport is usually anomalous and D ∞ ∼ K γ .…”