Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonaxisymmetric instabilities in turbulent electromagnetic pumps   The stability of annular electromagnetic pumps (EMPs) is investigated through
3D direct numerical simulations. When induction effects dominate dissipative
processes, linear induction EMPs become unstable and lead to non-axisymmetric
states relatively different from what was predicted by previous theoretical
models. We show that the 3D destabilization of the flow is deeply connected to
the axisymmetric state, and always appears as a secondary bifurcation from a
locally stalled flow, even if the applied magnetic field is axisymmetric.
Finally, we model a configuration aiming to optimize the efficiency of the
pump, by imposing electrical currents on both sides (inner and outer cylinders)
of the pump. This configuration increases the efficiency of the pump, but
generates a complex dynamics, associated to periodic oscillation of a large
vortex flow localized in the active region of the pump. Finally, we demonstrate
the existence of an upper bound on the efficiency of such electromagnetic pump,
which can never exceed 50%.

9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th