Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Transient flows and migration in granular suspensions: key role of
  Reynolds-like dilatancy   We investigate the transient dynamics of a sheared suspension of neutrally
buoyant particles under pressure-imposed conditions, subject to a sudden change
in shear rate or external pressure. Discrete Element Method simulations show
that, depending on the flow parameters (particle and system size, initial
volume fraction), the early stress response of the suspension may strongly
differ from the prediction of the Suspension Balance Model based on the
steady-state rheology. We show that a two-phase model incorporating the
Reynolds-like dilatancy law of Pailha & Pouliquen (2009), which prescribes the
dilation rate of the suspension over a strain scale $\gamma_0$, quantitatively
captures the suspension dilation/compaction over the whole range of parameters
investigated. Together with the Darcy flow induced by the pore pressure
gradient during dilation or compaction, this Reynolds-like dilatancy implies
that the early stress response of the suspension is nonlocal, with a nonlocal
length scale $\ell$ which scales with the particle size and diverges
algebraically at jamming. In regions affected by $\ell$, the stress level is
fixed, not by the steady-state rheology, but by the Darcy fluid pressure
gradient resulting from the dilation/compaction rate. Our results extend the
validity of the Reynolds-like dilatancy flow rule, initially proposed for
jammed suspensions, to flowing suspension below $\phi_\mathrm{c}$, thereby
providing a unified framework to describe dilation and shear-induced migration.
They pave the way for understanding more complex unsteady flows of dense
suspensions, such as impacts, transient avalanches or the impulsive response of
shear-thickening suspensions.

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The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
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The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
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The categories of this paper are: econ
12
The categories of this paper are: nucl-th