Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Capitalized Boussinesq approximation #1639

Merged
merged 2 commits into from May 14, 2017
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
2 changes: 1 addition & 1 deletion benchmarks/tangurnis/ba/tan.prm
Expand Up @@ -37,7 +37,7 @@ end

# This case of the benchmark uses the Boussinesq approximation.
subsection Formulation
set Formulation = custom # equivalent to boussinesq approximation
set Formulation = custom # equivalent to Boussinesq approximation
set Mass conservation = incompressible
set Temperature equation = reference density profile
end
Expand Down
22 changes: 11 additions & 11 deletions doc/manual/manual.tex
Expand Up @@ -1625,7 +1625,7 @@ \subsubsection{The truncated anelastic liquid approximation (TALA)}
The energy equation is the same as in the ALA case.

\subsubsection{The Boussinesq approximation (BA)}
\label{sec:boussinesq}
\label{sec:Boussinesq}

If we further assume that the reference temperature and the reference density are constant,
$\bar T(z)=T_0$, $\bar\rho(\bar p,\bar T)=\rho_0$,
Expand Down Expand Up @@ -1740,19 +1740,19 @@ \subsubsection{The Boussinesq approximation (BA)}
considered small, this naturally leads to the following variant of the the Boussinesq
model discussed above:
\begin{align}
\label{eq:stokes-1-boussinesq-linear}
\label{eq:stokes-1-Boussinesq-linear}
-\nabla \cdot \left[2\eta \varepsilon(\mathbf u)
\right] + \nabla p' &=
-\alpha\rho_0 T \mathbf g
& \qquad
& \textrm{in $\Omega$},
\\
\label{eq:stokes-2-boussinesq-linear}
\label{eq:stokes-2-Boussinesq-linear}
\nabla \cdot \mathbf u &= 0
& \qquad
& \textrm{in $\Omega$},
\\
\label{eq:temperature-boussinesq-linear}
\label{eq:temperature-Boussinesq-linear}
\rho_0 C_p \left(\frac{\partial T}{\partial t} + \mathbf u\cdot\nabla T\right)
- \nabla\cdot k\nabla T
&=
Expand All @@ -1761,14 +1761,14 @@ \subsubsection{The Boussinesq approximation (BA)}
& \textrm{in $\Omega$}.
\end{align}
Note that the right hand side forcing term
in \eqref{eq:stokes-1-boussinesq-linear} is now only the deviation of the
in \eqref{eq:stokes-1-Boussinesq-linear} is now only the deviation of the
gravitational force from the force that would act if the material were at
temperature $T_0$.

Under the assumption that all other coefficients are constant, one then
arrives at equations in which the only nonlinear term is the advection term,
$\mathbf u \cdot \nabla T$ in the temperature equation
\eqref{eq:temperature-boussinesq-linear}. This facilitates the use of a
\eqref{eq:temperature-Boussinesq-linear}. This facilitates the use of a
particular class of time stepping schemes in which one does not solve the whole
set of equations at once, iterating out nonlinearities as necessary, but
instead in each time step solves first the Stokes system with the previous
Expand Down Expand Up @@ -2005,13 +2005,13 @@ \subsubsection{Combined formulations}
(Section~\ref{sec:tala}).

\item
``boussinesq approximation'': This formulation sets the mass conservation approximation to ``incompressible'',
``Boussinesq approximation'': This formulation sets the mass conservation approximation to ``incompressible'',
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

this occurrence of the word needs to match what is being used in the .prm files. Did you change that as well?

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yes, that should be changed in all files where it occurs (this PR is just a recursive sed find-replace)

the temperature equation approximation to ``reference density profile'' and checks that neither
adiabatic nor shear heating are included in the list of heating plugins used in the model.
The default setting for the adiabatic conditions is a constant temperature, and hydrostatic
pressure and density profiles. This option should be chosen together with a material model
that defines a density that only depends on temperature and depth (and not on the pressure).
This is equivalent to the Boussinesq approximation (Section~\ref{sec:boussinesq}).
This is equivalent to the Boussinesq approximation (Section~\ref{sec:Boussinesq}).

\item
``isothermal compression'': This formulation sets the mass conservation approximation to
Expand Down Expand Up @@ -2075,7 +2075,7 @@ \subsubsection{Arbitrary Lagrangian-Eulerian implementation}
This scheme has the effect of choosing a minimally distorting perturbation to the mesh.
Because the mesh velocity is no longer zero in the ALE approach, we must then correct
the Eulerian advection terms in the advection system with the mesh velocity (see, e.g.
\cite{DHPR2004}). For instance, the temperature equation \eqref{eq:temperature-boussinesq-linear}
\cite{DHPR2004}). For instance, the temperature equation \eqref{eq:temperature-Boussinesq-linear}
becomes

\begin{equation*}
Expand Down Expand Up @@ -2154,7 +2154,7 @@ \subsection{Calculations with melt transport}
$\xi = \eta_0 \phi^{-n}$ with $n \approx 1$.

To avoid the density gradients in Equation~\eqref{eq:stokes-2-melt}, which would have to be specified individually
for each material model by the user, we can use the same method as for the mass conservation (described in Section~\ref{sec:boussinesq}) and assume the change in solid density is dominated by the change in static pressure,
for each material model by the user, we can use the same method as for the mass conservation (described in Section~\ref{sec:Boussinesq}) and assume the change in solid density is dominated by the change in static pressure,
which can be written as
$\nabla p_s \approx \nabla p_\text{static} \approx \rho_s \textbf{g}$.
This finally allows us to write
Expand Down Expand Up @@ -10046,7 +10046,7 @@ \subsubsection{Material models}
mentioned.

The function \texttt{is\_compressible} returns whether we should consider the
material as compressible or not, see Section~\ref{sec:boussinesq} on the
material as compressible or not, see Section~\ref{sec:Boussinesq} on the
Boussinesq model. As discussed there, incompressibility as described by this function
does not necessarily imply that the density is constant; rather, it
may still depend on temperature or pressure. In the current
Expand Down
4 changes: 4 additions & 0 deletions doc/modules/changes/20170514_myhill
@@ -0,0 +1,4 @@
Changed: The boussinesq approximation formulation is now
renamed to Boussinesq approximation.
<br>
(Bob Myhill, 2017/05/14)
2 changes: 1 addition & 1 deletion doc/modules/to-1.5.0.h
Expand Up @@ -104,7 +104,7 @@
* (Timo Heister, Juliane Dannberg, Rene Gassmoeller, 2016/12/18)
*
* <li> New: ASPECT now supports the choice between different formulations for
* the governing equations including boussinesq and anelastic liquid
* the governing equations including Boussinesq and anelastic liquid
* approximation. For this, the adiabatic conditions have been extended to
* provide values and gradients of the reference density. Several benchmarks
* for these formulations have been added.
Expand Down
3 changes: 3 additions & 0 deletions doc/update_prm_files_to_2.0.0.sed
Expand Up @@ -34,3 +34,6 @@ s/initial-conditions/initial-temperature/g
s/seismic vs/named additional outputs/g
s/seismic vp/named additional outputs/g
s/named additional outputs.*named additional outputs/named additional outputs/g

# Make all instances of boussinesq into Boussinesq
s/boussinesq/Boussinesq/g
2 changes: 1 addition & 1 deletion include/aspect/material_model/nondimensional.h
Expand Up @@ -32,7 +32,7 @@ namespace aspect
using namespace dealii;

/**
* A material model for incompressible (using the boussinesq approximation)
* A material model for incompressible (using the Boussinesq approximation)
* and compressible computations (with ALA or TALA) for a nondimensionalized
* problem. The viscosity is (optionally) depth and temperature dependent.
*
Expand Down
2 changes: 1 addition & 1 deletion include/aspect/parameters.h
Expand Up @@ -141,7 +141,7 @@ namespace aspect
return Formulation::isothermal_compression;
else if (input == "anelastic liquid approximation")
return Formulation::anelastic_liquid_approximation;
else if (input == "boussinesq approximation")
else if (input == "Boussinesq approximation")
return Formulation::boussinesq_approximation;
else if (input == "custom")
return Formulation::custom;
Expand Down
2 changes: 1 addition & 1 deletion source/simulator/parameters.cc
Expand Up @@ -322,7 +322,7 @@ namespace aspect
prm.enter_subsection("Formulation");
{
prm.declare_entry ("Formulation", "custom",
Patterns::Selection ("isothermal compression|custom|anelastic liquid approximation|boussinesq approximation"),
Patterns::Selection ("isothermal compression|custom|anelastic liquid approximation|Boussinesq approximation"),
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

this is an incompatible change -- we should discuss

"Select a formulation for the basic equations. Different "
"published formulations are available in ASPECT (see the list of "
"possible values for this parameter in the manual for available options). "
Expand Down
2 changes: 1 addition & 1 deletion tests/blankenbach_approximation.prm
Expand Up @@ -89,7 +89,7 @@ subsection Model settings
end

subsection Formulation
set Formulation = boussinesq approximation # this overwrites the parameters below
set Formulation = Boussinesq approximation # this overwrites the parameters below
set Mass conservation = implicit reference density profile
set Temperature equation = reference density profile
end
Expand Down
2 changes: 1 addition & 1 deletion tests/tangurnis_ba.prm
Expand Up @@ -65,7 +65,7 @@ subsection Adiabatic conditions model
end

subsection Formulation
set Formulation = boussinesq approximation
set Formulation = Boussinesq approximation
#set Mass conservation = incompressible
#set Temperature equation = reference density profile
end
Expand Down