Eddy diffusivity operator in homogeneous isotropic turbulence

Article Mechanics

Two-point stress-strain-rate correlation structure and non-local eddy viscosity in turbulent flows

Patricio Clark Di Leoni et al.

Summary: By analyzing the Karman-Howarth equation for filtered-velocity fields in turbulent flows, it is shown that the two-point correlation between the filtered strain-rate and subfilter stress tensors is central in the evolution of filtered-velocity correlation functions. Statistical a priori tests based on two-point correlations enable rigorous and physically meaningful studies of turbulence models. It is found that using fractional gradient orders rather than classical gradients in eddy-viscosity models can lead to stronger non-local correlations.

JOURNAL OF FLUID MECHANICS (2021)

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Article Physics, Fluids & Plasmas

Macroscopic forcing method: A tool for turbulence modeling and analysis of closures

Ali Mani et al.

Summary: The study presents a numerical procedure known as the macroscopic forcing method (MFM) to reveal differential operators acting on mean fields transported by underlying fluctuating flows, specifically the eddy diffusivity operator. The method is shown to accurately capture nonlocal mixing effects and has a cost-effective generalization for analysis of nonhomogeneous and wall-bounded flows.

PHYSICAL REVIEW FLUIDS (2021)

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Article Mechanics