Universality of anisotropic turbulence

We review some ideas about the physics of small-scale turbulent statistics, focusing on the scaling behavior of anisotropic fluctuations. We present results from direct numerical simulations of three-dimensional homogeneous, anisotropically forced, turbulent systems: the Rayleigh–Bénard system, the random-Kolmogorov-flow, and a third flow with constant anisotropic energy spectrum at low wave numbers. A comparison of the anisotropic scaling properties displays good similarity among these very different flows. Our findings support the conclusion that scaling exponents of anisotropic fluctuations are universal, i.e., independent of the forcing mechanism sustaining turbulence.