Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Energy conservation and gravity waves in sound-proof treatments of
  stellar interiors: Part II Lagrangian constrained analysis   The speed of sound greatly exceeds typical flow velocities in many stellar
and planetary interiors. To follow the slow evolution of subsonic motions,
various sound-proof models attempt to remove fast acoustic waves whilst
retaining stratified convection and buoyancy dynamics. In astrophysics,
anelastic models typically receive the most attention in the class of
sound-filtered stratified models. Generally, anelastic models remain valid in
nearly adiabatically stratified regions like stellar convection zones, but may
break down in strongly sub-adiabatic, stably stratified layers common in
stellar radiative zones. However, studying stellar rotation, circulation, and
dynamos requires understanding the complex coupling between convection and
radiative zones, and this requires robust equations valid in both regimes. Here
we extend the analysis of equation sets begun in Brown Vasil & Zweibel 2012,
which studied anelastic models, to two types of pseudo-incompressible models.
This class of models has received attention in atmospheric applications, and
more recently in studies of white-dwarf supernovae progenitors. We demonstrate
that one model conserves energy but the other does not. We use Lagrangian
variational methods to extend the energy conserving model to a general equation
of state, and dub the resulting equation set the Generalized
Pseudo-Incompressible (GPI) model. We show that the GPI equations suitably
capture low frequency phenomena in both convection and radiative zones in stars
and other stratified systems, and we provide recommendations for converting
low-Mach number codes to this equation set.

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The categories of this paper are: eess
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The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: plasm-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: supr-con