Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Calibrating passive scalar transport in shear-flow turbulence   The turbulent diffusivity tensor is determined for linear shear flow
turbulence using numerical simulations. For moderately strong shear, the
diagonal components are found to increase quadratically with Peclet and
Reynolds numbers below about 10 and then become constant. The diffusivity
tensor is found to have components proportional to the symmetric and
antisymmetric parts of the velocity gradient matrix, as well as products of
these. All components decrease with the wave number of the mean field in a
Lorentzian fashion. The components of the diffusivity tensor are found not to
depend significantly on the presence of helicity in the turbulence. The signs
of the leading terms in the expression for the diffusion tensor are found to be
in good agreement with estimates based on a simple closure assumption.

20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin