Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A robust method for calculating interface curvature and normal vectors
  using an extracted local level set   The level-set method is a popular interface tracking method in two-phase flow
simulations. An often-cited reason for using it is that the method naturally
handles topological changes in the interface, e.g. merging drops, due to the
implicit formulation. It is also said that the interface curvature and normal
vectors are easily calculated. This last point is not, however, the case in the
moments during a topological change, as several authors have already pointed
out. Various methods have been employed to circumvent the problem. In this
paper, we present a new such method which retains the implicit level-set
representation of the surface and handles general interface configurations. It
is demonstrated that the method extends easily to 3D. The method is validated
on static interface configurations, and then applied to two-phase flow
simulations where the method outperforms the standard method and the results
agree well with experiments.

30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an