Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Surface jets and internal mixing during the coalescence of impacting and
  sessile droplets   The internal dynamics during the coalescence of a sessile droplet and a
subsequently deposited impacting droplet, with either identical or distinct
surface tension, is studied experimentally in the regime where surface tension
is dominant. Two color high-speed cameras are used to capture the rapid
internal flows and associated mixing from both side and bottom views
simultaneously by adding an inert dye to the impacting droplet. Given
sufficient lateral separation between droplets of identical surface tension, a
robust surface jet is identified on top of the coalesced droplet. Image
processing shows this jet is the result of a surface flow caused by the impact
inertia and an immobile contact line. By introducing surface tension
differences between the coalescing droplets, the surface jet can be either
enhanced or suppressed via a Marangoni flow. The influence of the initial
droplet configuration and relative surface tension on the long-term dynamics
and mixing efficiency, plus the implications for emerging applications such as
reactive inkjet printing, are also considered.

13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
6
The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int