Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multi-Scale Turbulence Injector: a new tool to generate intense
  homogeneous and isotropic turbulence for premixed combustion   Nearly homogeneous and isotropic, highly turbulent flow, generated by an
original multi-scale injector is experimentally studied. This multi-scale
injector is made of three perforated plates shifted in space such that the
diameter of their holes and their blockage ratio increase with the downstream
distance. The Multi-Scale Turbulence Injector (hereafter, MuSTI) is compared
with a Mono-Scale Turbulence Injector (MoSTI), the latter being constituted by
only the last plate of MuSTI. This comparison is done for both cold and
reactive flows. For the cold flow, it is shown that, in comparison with the
classical mono-scale injector, for the MuSTI injector: (i) the turbulent
kinetic energy is roughly twice larger, and the kinetic energy supply is
distributed over the whole range of scales. This is emphasized by second and
third order structure functions. (ii) the transverse fluxes of momentum and
energy are enhanced, (iii) the homogeneity and isotropy are reached earlier
($\approx 50$%), (iv) the jet merging distance is the relevant scaling
length-scale of the turbulent flow, (v) high turbulence intensity ($\approx
15$%) is achieved in the homogeneous and isotropic region, although the
Reynolds number based on the Taylor microscale remains moderate ($Re_\lambda
\approx 80$). In a second part, the interaction between the multi-scale
generated turbulence and the premixed flame front is investigated by laser
tomography. A lean V-shaped methane/air flame is stabilised on a heated rod in
the homogeneous and isotropic region of the turbulent flow. The main
observation is that the flame wrinkling is hugely amplified with the
multi-scale generated injector, as testified by the increase of the flame brush
thickness.

14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph