Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Short-time evolution of Lagrangian velocity gradient correlations in
  isotropic turbulence   We show by direct numerical simulation (DNS) that the Lagrangian cross
correlation of velocity gradients in homogeneous isotropic turbulence increases
at short times, whereas its auto-correlation decreases. Kinematic
considerations allow to show that two invariants of the turbulent velocity
field determine the short-time velocity gradient correlations. In order to get
a more intuitive understanding of the dynamics for longer times, heuristic
models are proposed involving the combined action of local shear and rotation.
These models quantitatively reproduce the effects and disentangle the different
physical mechanisms leading to the observations in the DNS.

27
The categories of this paper are: comp-gas
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The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th