Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On droplets coalescence in a quasi-2D fluid   The coalescence of droplets plays a crucial role in nature and modern
technology. Various experimental and theoretical studies explored droplet
dynamics in 3D and on 2D solid or liquid substrates. In this paper, we
demonstrate the coalescence of isotropic droplets confined in thin quasi-2D
liquids -- overheated smectic films. We observe the merging of micrometer-sized
flat droplets using high-speed-imaging and analyse the shape transformations of
the droplets on the timescale of milliseconds. Our studies reveal the scaling
laws of the coalescence time, which exhibits a different dependence on the
droplet geometry than in case of droplets on a solid substrate. A theoretical
model is proposed to explain the difference in behaviour.

9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess