Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Turbulent channel flow of finite-size spherical particles with viscous
  hyper-elastic walls   We study single-phase and particulate turbulent channel flows, bounded by two
incompressible hyper-elastic walls. Different wall elasticities are considered
with and without a 10% volume fraction of finite-size rigid spherical
particles, while elastic walls are modelled as a neo-Hookean material. We
report a significant drag increase and an enhancement of the turbulence
activity with growing wall elasticity for both single-phase and particulate
cases in comparison with the single-phase flow over rigid walls. A drag
reduction and a turbulence attenuation is obtained for the particulate cases
with highly elastic walls, albeit with respect to the single-phase flow of the
same wall elasticity; whereas, an opposite effect of the particles is observed
on the flow of the less elastic walls. This is explained by investigating the
near-wall turbulence of highly elastic walls, where the strong asymmetry in the
magnitude of wall-normal velocity fluctuations (favouring the positive), is
found to push the particles towards the channel centre. The particle layer
close to the wall is shown to contribute to the turbulence production by
increasing the wall-normal velocity fluctuations, while in the absence of this
layer, smaller wall deformation and in turn a turbulence attenuation is
observed. We further address the effect of the volume fraction at a moderate
wall elasticity, by increasing the particle volume fraction up to 20%.
Migration of the particles from the interface region is found to be the cause
of a further turbulence attenuation, in comparison to the same volume fraction
in the case of rigid walls. However, the particle induced stress compensates
for the loss of the Reynolds shear stress, thus, resulting in a higher overall
drag for the case with elastic walls. The effect of wall-elasticity on the drag
is reported to reduce significantly with increasing volume fraction of
particles.

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The categories of this paper are: q-alg
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The categories of this paper are: chem-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: math
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The categories of this paper are: nucl-ex
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The categories of this paper are: supr-con
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ph
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org