Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Modulation-resonance mechanism for surface waves in a two-layer fluid
  system   We propose a Boussinesq-type model to study the surface/interfacial wave
manifestation of an underlying, slowly-varying, long-wavelength, baroclinic
flow in a two-layer, density-stratified system. The results of our model show
numerically that, under strong nonlinearity, surface waves, with their typical
wavenumber being the resonant $k_{\mathrm{res}}$, can be generated locally at
the leading edge of the underlying slowly-varying, long-wavelength baroclinic
flow. Here, the resonant $k_{\mathrm{res}}$ satisfies the class 3 triad
resonance condition among two short-mode waves and one long-mode wave in which
all waves propagate in the same direction. Moreover, when the slope of the
baroclinic flow is sufficiently small, only one spatially-localized
large-amplitude surface wave packet can be generated at the leading edge. This
localized surface wave packet becomes high in amplitude and large in group
velocity after the interaction with its surrounding waves. These results are
qualitatively consistent with various experimental observations including
resonant surface waves at the leading edge of an internal wave. Subsequently,
we propose a mechanism, referred to as the modulation-resonance mechanism,
underlying these surface phenomena, based on our numerical simulations. The
proposed modulation-resonance mechanism combines the linear modulation
(ray-based) theory for the spatiotemporal asymmetric behavior of surface waves
and the nonlinear class 3 triad resonance theory for the energy focusing of
surface waves around the resonant wavenumber $k_{\mathrm{res}}$ in Fourier
space.

2
The categories of this paper are: math
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph