This utility now always creates two patches, and only creates duplicate
faces when they connect to different cells and point in opposite
directions. Now that ACMI has been removed, there is no need to create
duplicate faces on the same cell and with similar orientations. This is
unituitive and is now considered an invalid mesh topology.
The preferred syntax for createBaffles is now as follows:
internalFacesOnly true;
baffles
{
cyclics
{
type faceZone;
zoneName cyclicFaces;
owner
{
name cyclicLeft;
type cyclic;
neighbourPatch cyclicRight;
}
neighbour
{
name cyclicRight;
type cyclic;
neighbourPatch cyclicLeft;
}
}
}
Note that the 'patches' sub-dictionary is not needed any more; the
'owner' and 'neighbour' sub-dictionaries can be in the same dictionary
as the parameters with which faces are selected. For backwards
compatibility, however, a 'patches' sub-dictionary is still permitted,
as are keywords 'master' and 'slave' (in place of 'owner' and
'neighbour', respectively).
The 'patchPairs' syntax has been removed. Whilst consise, this syntax
made a number of assumptions and decisions regarding naming conventions
that were not sufficiently intuitive for the user to understand without
extensive reference to the code. If identical boundaries are desired on
both sides of the patch, dictionary substitution provides a more
intuitive way of minimising the amount of specifiection required. For
example, to create two back-to-back walls, the following specification
could be used:
internalFacesOnly true;
fields true;
baffles
{
walls
{
type faceZone;
zoneName wallFaces;
owner
{
name baffleWallLeft;
type wall;
patchFields
{
p
{
type zeroGradient;
}
U
{
type noSlip;
}
}
}
neighbour
{
name baffleWallRight;
$owner; // <-- Use the same settings as for the owner
}
}
}
The following examples in the tutorials ($FOAM_TUTORIALS) directory have
been converted from using AMI to the new NCC system:
+ compressible/rhoPimpleFoam/RAS/annularThermalMixer
+ incompressible/pimpleFoam/RAS/propeller
+ lagrangian/particleFoam/mixerVessel2D (formerly mixerVesselAMI2D)
+ multiphase/interFoam/RAS/mixerVessel
+ multiphase/interFoam/RAS/propeller
+ multiphase/multiphaseEulerFoam/laminar/mixerVessel2D (formerly mixerVesselAMI2D)
The following tutorial has been converted from using ACMI:
+ incompressible/pimpleFoam/RAS/oscillatingInlet
The following tutorial has been converted from using Repeat AMI:
+ incompressible/pimpleFoam/RAS/impeller
The following tutorial has been added to demonstrate NCC's ability to
create a sufficiently conservative solution in a closed domain to
maintain phase fraction boundedness:
+ multiphase/interFoam/laminar/mixerVessel2D
The following tutorials have been added to demonstrate NCC's ability to
simulate partially overlapping couples on curved surfaces:
+ incompressible/pimpleFoam/RAS/ballValve
+ multiphase/compressibleInterFoam/RAS/ballValve
The following tutorial has been added to provide a simple comparison of
the conservation behaviour of AMI and NCC:
+ incompressible/pimpleFoam/laminar/nonConformalChannel
The following tutorial has been removed, as there were sufficiently many
examples involving this geometry:
+ incompressible/pimpleFoam/laminar/mixerVesselAMI2D
On unstructured collocated meshes the Reynolds stress tends to decouple from the
velocity creating pronounced staggering patterns in the solution. This effect
is reduced or eliminated by a special coupling algorithm which replaces the
gradient diffusion component of the Reynolds stress with the equivalent compact
representation on the mesh, i.e. div-grad with Laplacian in the DivDevRhoReff function:
template<class BasicMomentumTransportModel>
template<class RhoFieldType>
Foam::tmp<Foam::fvVectorMatrix>
Foam::ReynoldsStress<BasicMomentumTransportModel>::DivDevRhoReff
(
const RhoFieldType& rho,
volVectorField& U
) const
{
tmp<volTensorField> tgradU = fvc::grad(U);
const volTensorField& gradU = tgradU();
const surfaceTensorField gradUf(fvc::interpolate(gradU));
// Interpolate Reynolds stress to the faces
// with either a stress or velocity coupling correction
const surfaceVectorField Refff
(
(this->mesh().Sf() & fvc::interpolate(R_))
// Stress coupling
+ couplingFactor_
*(this->mesh().Sf() & fvc::interpolate(this->nut()*gradU))
// or velocity gradient coupling
// + couplingFactor_
// *fvc::interpolate(this->nut())*(this->mesh().Sf() & gradUf)
- fvc::interpolate(couplingFactor_*this->nut() + this->nu())
*this->mesh().magSf()*fvc::snGrad(U)
- fvc::interpolate(this->nu())*(this->mesh().Sf() & dev2(gradUf.T()))
);
return
(
fvc::div(fvc::interpolate(this->alpha_*rho)*Refff)
- correction(fvm::laplacian(this->alpha_*rho*this->nuEff(), U))
);
}
In the above two options for the coupling term are provided, one based on the
stress correction (un-commented) and an alternative based an the velocity
gradient correction (commented). Tests run so far indicate that the stress
correction provides better coupling while minimising the error introduced.
A new tutorial case ductSecondaryFlow is provided which demonstrates the updated
coupling algorithm on the simulation of the classic secondary flow generated in
rectangular ducts.
It is not clear for what cases the minVol control is useful or necessary and for
some cases it causes problems with snapping and layer addition if not set to a
sufficiently small value.
motionSmootherAlgoCheck::checkMesh is used by snappyHexMesh to check the mesh
after snapping and morphing. The minVol test which checks for collapsed cells
is now relative to the cube of the minimum bounding box length so that it is
less dependent on the size of the geometry and less likely to need changing for
very small geometries.
The default value is set in
etc/caseDicts/mesh/generation/meshQualityDict
etc/caseDicts/mesh/generation/meshQualityDict.cfg
//- Minimum cell pyramid volume relative to min bounding box length^3
// Set to a fraction of the smallest cell volume expected.
// Set to very negative number (e.g. -1e30) to disable.
minVol 1e-10;
The unused minArea and minTriangleTwist tests have been removed
for consistency with the regionToCell topo set source and splitMeshRegions and
provides more logical extension to the multiple and outside point variants insidePoints,
outsidePoint and outsidePoints.
When using 'simple' or 'hierarchical' decomposition it is useful to slightly rotate a
coordinate-aligned block-mesh to improve the processor boundaries by avoiding
irregular cell distribution at those boundaries. The degree of slight rotation
is controlled by the 'delta' coefficient and a value of 0.001 is generally
suitable so to avoid unnecessary clutter in 'decomposeParDict' 'delta' now
defaults to this value.
The FOAM file format has not changed from version 2.0 in many years and so there
is no longer a need for the 'version' entry in the FoamFile header to be
required and to reduce unnecessary clutter it is now optional, defaulting to the
current file format 2.0.
The inside or outside region refinement level is now specified using the simple
"level <level>" entry in refinementRegions e.g.
refinementRegions
{
refinementBox
{
mode inside;
level 5;
}
}
rather than
refinementRegions
{
refinementBox
{
mode inside;
levels ((1E15 5));
}
}
where the spurious "1E15" number is not used and the '((...))' is unnecessary clutter.
Originally the only supported geometry specification were triangulated surfaces,
hence the name of the directory: constant/triSurface, however now that other
surface specifications are supported and provided it is much more logical that
the directory is named accordingly: constant/geometry. All tutorial and
template cases have been updated.
Note that backward compatibility is provided such that if the constant/geometry
directory does not exist but constant/triSurface does then the geometry files
are read from there.
The phase-change functionality in interPhaseChangeFoam has been generalised and
moved into the run-time selectable twoPhaseChange library included into
interFoam providing optional phase-change. The three cavitation models provided
in interPhaseChangeFoam are now included in the twoPhaseChange library and the
two interPhaseChangeFoam cavitation tutorials updated for interFoam.
interPhaseChangeFoam has been replaced by a user redirection script which prints
the following message:
The interPhaseChangeFoam solver has solver has been replaced by the more general
interFoam solver, which now supports phase-change using the new twoPhaseChange
models library.
To run with with phase-change create a constant/phaseChangeProperties dictionary
containing the phase-change model specification, e.g.
phaseChangeModel SchnerrSauer;
pSat 2300; // Saturation pressure
See the following cases for an example converted from interPhaseChangeFoam:
$FOAM_TUTORIALS/multiphase/interFoam/laminar/cavitatingBullet
$FOAM_TUTORIALS/multiphase/interFoam/RAS/propeller
