Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The inexorable resistance of inertia determines the initial regime of
  drop coalescence   Drop coalescence is central to diverse processes involving dispersions of
drops in industrial, engineering and scientific realms. During coalescence, two
drops first touch and then merge as the liquid neck connecting them grows from
initially microscopic scales to a size comparable to the drop diameters. The
curvature of the interface is infinite at the point where the drops first make
contact, and the flows that ensue as the two drops coalesce are intimately
coupled to this singularity in the dynamics. Conventionally, this process has
been thought to have just two dynamical regimes: a viscous and an inertial
regime with a crossover region between them. We use experiments and simulations
to reveal that a third regime, one that describes the initial dynamics of
coalescence for all drop viscosities, has been missed. An argument based on
force balance allows the construction of a new coalescence phase diagram.

12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ