Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mechanism of flame acceleration and detonation transition from the
  interaction of a supersonic turbulent flame with an obstruction   The present paper seeks to determine the mechanism of flame acceleration and
transition to detonation when a turbulent flame preceded by a shock interacts
with a single obstruction in its path, taken as a cylindrical obstacle or a
wall in the present study. The problem is addressed experimentally in a mixture
of propane-oxygen at sub-atmospheric conditions. The turbulent flame was
generated by passing a detonation wave through a perforated plate, yielding
flames with turbulent burning velocities 10 to 20 larger than the laminar
values and incident shock Mach numbers ranging between 2 and 2.5. Time resolved
schlieren videos recorded at approximately 100 kHz and numerical reconstruction
of the flow field permitted to determine the mechanism of flame acceleration
and transition to detonation. It was found to be the enhancement of the
turbulent burning rate of the flame through its interaction with the shock
reflection on the obstacle. The amplification of the burning rate was found to
drive the flame burning velocity close to the speed of sound with respect to
the fresh gases, resulting in the amplification of a shock in front of the
flame. The acceleration through this regime resulted in the strengthening of
this shock. Detonation was observed in regions of non-planarity of this
internal shock, inherited by the irregular shape of the turbulent flame itself.
Auto-ignition at early times of this process was found to be negligibly slow
compared with the flow evolution time scale in the problem investigated,
suggesting that the relevant time scale is primarily associated with the
increase in turbulent burning rate by the interaction with reflected shocks.

15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph