Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Equations for two-phase flows: a primer   The main goal of these notes is to give a review of the equations for two
phase flow problems with an interface between the two phases in a
self-contained way, and, in particular, to properly include surface tension
into the interface balance equations.

21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg