Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: 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 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.

12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
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The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
30
The categories of this paper are: q-alg