Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A model for unsteady mixed flows in non uniform closed water pipes and a
  well-balanced finite volume scheme   We present the derivation of a new unidirectional model for We present the
derivation of a new unidirectional model for unsteady mixed flows in non
uniform closed water pipes. We introduce a local reference frame to take into
account the local perturbation caused by the changes of section and slope. Then
an asymptotic analysis is performed to obtain a model for free surface flows
and another one for pressurized flows. By coupling these models through the
transition points by the use of a common set of variables and a suitable
pressure law, we obtain a simple formulation called PFS-model close to the
shallow water equations with source terms. It takes into account the changes of
section and the slope variation in a continuous way through transition points.
Transition point between the two types of flows is treated as a free boundary
associated to a discontinuity of the gradient of pressure. The numerical
simulation is performed by making use of a Roe-like finite volume scheme that
we adapted to take into account geometrical source terms in the convection
matrix. Finally some numerical tests are presented.

21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th