For some systems the thermal coupling between the solid and fluid regions
dominates overall convergence and it may be beneficial to sub-iterate over the
thermal system as the energy solution is cheaper than the pressure-velocity
system. To test this the new optional nEcorr entry in system/fvSolution is
provided which defaults to 1, e.g.
PIMPLE
{
nOuterCorrectors 1;
nEcorr 2;
}
If this proves useful it could be extended and improved by adding convergence
controls.
Note that the solution of the solid regions is now before the fluid regions as
it make more sense if solid regions are sources or sinks of heat to solve them
before the fluid.
Description
Transport package using the Andrade function for the natural logarithm of
dynamic viscosity and thermal conductivity of liquids:
\verbatim
log(mu) = muCoeffs[0] + muCoeffs[1]*T + muCoeffs[2]*sqr(T)
+ muCoeffs_[3]/(muCoeffs_[4] + T)
log(kappa) = kappaCoeffs[0] + kappaCoeffs[1]*T + kappaCoeffs[2]*sqr(T)
+ kappaCoeffs_[3]/(kappaCoeffs_[4] + T)
);
\endverbatim
References:
\verbatim
Andrade, E. D. C. (1934).
XLI. A theory of the viscosity of liquids.—Part I.
The London, Edinburgh, and Dublin Philosophical Magazine
and Journal of Science, 17(112), 497-511.
Andrade, E. D. C. (1934).
LVIII. A theory of the viscosity of liquids.—Part II.
The London, Edinburgh, and Dublin Philosophical Magazine
and Journal of Science, 17(113), 698-732.
\endverbatim
Usage
\table
Property | Description
muCoeffs | Dynamic viscosity polynomial coefficients
kappaCoeffs | Thermal conductivity polynomial coefficients
\endtable
Example of the specification of the transport properties for water@200bar:
\verbatim
transport
{
muCoeffs (-25.8542 0.031256 -2.2e-05 3289.918 -11.4784);
kappaCoeffs (-2.56543 0.008794 -9.8e-06 100.368 0);
}
\endverbatim
By default a streamline now stops at the cyclic and starts again at the
coupled location on the opposite cyclic.
There is also now an "outside" option that can be passed to the
streamlines function. This changes the default behaviour so that the
streamline continues outside of the mesh when it encounters a cyclic
patch. The following postProcess command uses the "outside" option in
this way:
postProcess -latestTime -func "
streamlinesPatch
(
patch=inlet,
nPoints=50,
outside=true,
fields=(p U)
)"
This prevents excessive duplication of surface geometry and makes
post-processing tasks in paraview more convenient.
The Nastran and Star-CD surface formats were found not to work, so
support for these output types has been removed. Raw, VTK, Foam and
Ensight formats are all still available.
for e.g. load-balancing. The fvMeshDistributor is selected via the new optional
distributor entry in dynamicMeshDict, e.g.
distributor
{
type decomposer;
libs ("libfvMeshDistributors.so");
}
Note that currently only the framework is included in this commit, the
fvMeshDistributors library is not yet fully functional and hence not released
yet.
This improves convergence of some steady-state chtMultiRegionFoam (which uses
the pEqn.H from buoyantPimpleFoam) cases but does not affect transient
simulations unless aggressive pressure relaxation is applied, i.e. transient
SIMPLE.
When limiting the pressure in p_rgh based solvers p typically has calculated BCs
which are now supported when calculating the max and min pressure from maxFactor
and minFactor.
The surfaceVectorField Uf is used instead of the flux field phi for ddtPhiCorr
in moving mesh cases to handle linear and rotating motion and must mapped from
the volVectorField U to new faces created by cell splitting or merging in mesh
refinement/unrefinement.
With the general run-time selectable fvMeshMovers engine compression simulations
can be performed with reactingFoam so there is no longer any need for engine
specific solvers or engineMesh.
An engineFoam script is provided to redirect users to reactingFoam with
instructions.
PDRFoam is a Xi combustion model solver including porosity distributed
resistance and shares code with XiFoam so it is more logical that it should be
in a sub-directory of XiFoam to simplify compilation dependency.
With the general run-time selectable fvMeshMovers engine compression simulations
can be performed with rhoPimpleFoam so there is no longer any need for engine
specific solvers.
A coldEngineFoam script is provided to redirect users to rhoPimpleFoam with
instructions.
With the addition of mesh-motion to XiFoam and the new engine fvMeshMover the
XiEngineFoam kivaTest simple IC engine example now runs in XiFoam and
XiEngineFoam has been removed. This simplifies maintenance provides greater
extensibility.
with the run-time selectable engine userTime embedded in Time.
All parts of the original engineTime relating to the engine geometry have been
moved to engineMesh. This is part of the process of integrating engine
simulations within the standard moving-mesh solvers.
The floatingObject tutorial has been update to demonstrate this functionality by
adding the following topoChanger entry to dynamicMeshDict:
topoChanger
{
type refiner;
libs ("libfvMeshTopoChangers.so");
// How often to refine
refineInterval 1;
// Field to be refinement on
field alpha.water;
// Refine field in between lower..upper
lowerRefineLevel 0.001;
upperRefineLevel 0.999;
// Have slower than 2:1 refinement
nBufferLayers 1;
// Refine cells only up to maxRefinement levels
maxRefinement 1;
// Stop refinement if maxCells reached
maxCells 200000;
// Flux field and corresponding velocity field. Fluxes on changed
// faces get recalculated by interpolating the velocity. Use 'none'
// on surfaceScalarFields that do not need to be reinterpolated.
correctFluxes
(
(phi none)
(nHatf none)
(rhoPhi none)
(alphaPhi.water none)
(meshPhi none)
(ghf none)
);
// Write the refinement level as a volScalarField
dumpLevel true;
}
Note that currently only single rigid body motion is supported (but multi-body
support will be added shortly) and the Crank-Nicolson scheme is not supported.
This boundary condition specifies a slip velocity on moving walls. It
works similarly to movingWallVelocity, except that the tangential
velocity is not constrained. It can be specified as follows:
<patchName>
{
type movingWallSlipVelocity;
value uniform (0 0 0); // Initial value
}
