Asymmetry of velocity increments in turbulence

• DOI: 10.1103/physrevresearch.4.l042002
• Publication Date: 2022-10-04T10:01:06Z
• Authors: Katepalli R. Sree...; Kartik P. Iyer; Ashvin Vinodh
• Keywords: Physics; QC1-999; 0103 physical sciences; Fluid Dynamics (physics.flu-dyn); FOS: Physical sciences; Physics - Fluid Dynamics; Chaotic Dynamics (nlin.CD); Nonlinear Sciences - Chaotic Dynamics; 01 natural sciences

We use well-resolved direct numerical simulations of high-Reynolds-number turbulence to study a fundamental statistical property of turbulence -- the asymmetry of velocity increments -- with likely implications on important dynamics. This property, ignored by existing small-scale phenomenological models, manifests most prominently in the non-monotonic trend of velocity increment moments (or structure functions) with the moment order, and in differences between ordinary and absolute structure functions for a given separation distance. We show that high-order structure functions arise nearly entirely from the negative side of the probability density of velocity increments, essentially removing the ambiguity between ordinary and absolute moments, and provide a plausible dynamical interpretation of this result.