Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spontaneous spinning of a dichloromethane drop on an aqueous surfactant
  solution   We report a series of experiments carried out with a dichloromethane drop
deposited on the surface of an aqueous solution containing a surfactant,
cetyltrimethylammonium bromide. After an induction stage during which the drop
stays axisymmetric, oscillations occur along the contact line. These
oscillations are succeeded by a spectacular spontaneous spinning of the drop.
The latter quickly takes the form of a two-tip `rotor' and the spinning rate
stabilizes at a constant value, no longer varying despite the gradual changes
of the drop shape and size. The drop eventually disappears due to the continual
dissolution and evaporation of dichloromethane. Schlieren visualizations and
particle image velocimetry are used to establish a consistent scenario capable
of explaining the evolution of the system. The Marangoni effect induced by the
dissolution of dichloromethane in the drop vicinity is shown to be responsible
for the observed dynamics. Arguments borrowed from dynamical systems theory and
from an existing low-order model allow us to explain qualitatively why the
system selects the spinning configuration. The geometry of the immersed part of
the drop is shown to play a crucial role in this selection process, as well as
in the regulation of the spinning rate.

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The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
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The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: chem-ph
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The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas