Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Application of Helmholtz-Hodge decomposition and conditioned structure
  functions to exploring influence of premixed combustion on turbulence
  upstream of the flame   In order to explore the influence of combustion-induced thermal expansion on
turbulence, a new research method is introduced. The method consists in jointly
applying Helmholtz-Hodge decomposition and conditioned structure functions to
analyzing turbulent velocity fields. Opportunities offered by the method are
demonstrated by using it to process Direct Numerical Simulation data obtained
earlier from two statistically 1D, planar, fully-developed, weakly turbulent,
single-step-chemistry, premixed flames characterized by two significantly
different (7.52 and 2.50) density ratios, with all other things being
approximately equal. To emphasize the influence of combustion-induced thermal
expansion on turbulent flow of unburned mixture upstream of a premixed flame,
the focus of analysis is placed on structure functions conditioned to the
unburned mixture in both points. Two decomposition techniques, i.e. (i) a
widely used orthogonal Helmholtz-Hodge decomposition and (ii) a recently
introduced natural Helmholtz-Hodge decomposition, are probed, with results
obtained using them being similar in the largest part of the computational
domain with the exception of narrow zones near the inlet and outlet boundaries.
Computed results indicate that combustion-induced thermal expansion can
significantly change turbulent flow of unburned mixture upstream of a premixed
flame by generating anisotropic potential velocity fluctuations whose spatial
structure differ substantially from spatial structure of the incoming
turbulence. The magnitude of such potential velocity fluctuations is greater
than the magnitude of the solenoidal velocity fluctuations in the largest part
of the mean flame brush in the case of the high density ratio. In the case of
the low density ratio, the latter magnitude is larger everywhere, but the two
magnitudes are comparable in the middle of the mean flame brush.

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The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph