Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unsteady Stokes flow near boundaries: the point-particle approximation
  and the method of reflections   Problems of particle dynamics involving unsteady Stokes flows in confined
geometries are typically harder to solve than their steady counterparts.
Approximation techniques are often the only resort. Felderhof (see e.g. 2005,
2009b) has developed a point-particle approximation framework to solve such
problems, especially in the context of Brownian motion. Despite excellent
agreement with past experiments, this framework has an inconsistency which we
address in this work. Upon implementing our modifications, the framework passes
consistency checks that it previously failed. Further, it is not obvious that
such an approximation should work for short time-scale motion. We investigate
its validity by deriving it from a general formalism based on integral
equations through a series of systematic approximations. We also compare
results from the point-particle framework against a calculation performed using
the method of reflections, for the specific case of a sphere near a full-slip
plane boundary. We find from our analysis that the reasons for the success of
the point-particle approximation are subtle and have to do with the nature of
the unsteady Oseen tensor. Finally, we provide numerical predictions for
Brownian motion near a full-slip and a no-slip plane wall based on the
point-particle approximation as used by Felderhof, our modified point-particle
approximation, and the method of reflections. We show that our modifications to
Felderhof's framework would become significant for systems of metallic
nanoparticles in liquids.

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The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: ao-sci
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The categories of this paper are: stat
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The categories of this paper are: nucl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: cs
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The categories of this paper are: mtrl-th