Large-Eddy Simulation closures of passive scalar turbulence: a systematic approach

The issue of the parameterization of small scale (``subgrid'') turbulence is addressed in the context of passive scalar transport. We focus on the Kraichnan advection model which lends itself to the analytical investigation of the closure problem. We derive systematically the dynamical equ...

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Bibliographic Details
Published in:arXiv.org 2003-09
Main Authors: M Martins Afonso, Celani, A, Festa, R, Mazzino, A
Format: Article
Language:English
Subjects:
Closures
Computational fluid dynamics
Computer simulation
Large eddy simulation
Parameterization
Turbulence
Vortices
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Summary:The issue of the parameterization of small scale (``subgrid'') turbulence is addressed in the context of passive scalar transport. We focus on the Kraichnan advection model which lends itself to the analytical investigation of the closure problem. We derive systematically the dynamical equations which rule the evolution of the coarse-grained scalar field. At the lowest-order approximation in \(l/r\), \(l\) being the characteristic scale of the filter defining the coarse-grained scalar field and \(r\) the inertial range separation, we recover the classical eddy-diffusivity parameterization of small scales. At the next-leading order a dynamical closure is obtained. The latter outperforms the classical model and is therefore a natural candidate for subgrid modelling of scalar transport in generic turbulent flows.
ISSN:2331-8422
DOI:10.48550/arxiv.0305055