providing the shear-stress term in the momentum equation for incompressible and
compressible Newtonian, non-Newtonian and visco-elastic laminar flow as well as
Reynolds averaged and large-eddy simulation of turbulent flow.
The general deviatoric shear-stress term provided by the MomentumTransportModels
library is named divDevTau for compressible flow and divDevSigma (sigma =
tau/rho) for incompressible flow, the spherical part of the shear-stress is
assumed to be either included in the pressure or handled separately. The
corresponding stress function sigma is also provided which in the case of
Reynolds stress closure returns the effective Reynolds stress (including the
laminar contribution) or for other Reynolds averaged or large-eddy turbulence
closures returns the modelled Reynolds stress or sub-grid stress respectively.
For visco-elastic flow the sigma function returns the effective total stress
including the visco-elastic and Newtonian contributions.
For thermal flow the heat-flux generated by thermal diffusion is now handled by
the separate ThermophysicalTransportModels library allowing independent run-time
selection of the heat-flux model.
During the development of the MomentumTransportModels library significant effort
has been put into rationalising the components and supporting libraries,
removing redundant code, updating names to provide a more logical, consistent
and extensible interface and aid further development and maintenance. All
solvers and tutorials have been updated correspondingly and backward
compatibility of the input dictionaries provided.
Henry G. Weller
CFD Direct Ltd.
The utilised static parts of polyMeshGeometry are now part of a
polyMeshCheck namespace. Everything else has been removed, as they were
unused, out of date, and/or duplicated elsewhere.
For many information and diagnostic messages the absolute path of the object is
not required and the local path relative to the current case is sufficient; the
new localObjectPath() member function of IOobject provides a convenient way of
printing this.
The calculation and input/output of transformations has been rewritten
for all coupled patches. This replaces multiple duplicated, inconsistent
and incomplete implementations of transformation handling which were
spread across the different coupled patch types.
Transformations are now calculated or specified once, typically during
mesh construction or manipulation, and are written out with the boundary
data. They are never re-calculated. Mesh changes should not change the
transformation across a coupled interface; to do so would violate the
transformation.
Transformations are now calculated using integral properties of the
patches. This is more numerically stable that the previous methods which
functioned in terms of individual faces. The new routines are also able
to automatically calculate non-zero centres of rotation.
The user input of transformations is backwards compatible, and permits
the user to manually specify varying amounts of the transformation
geometry. Anything left unspecified gets automatically computed from the
patch geometry. Supported specifications are:
1) No specification. Transformations on cyclics are automatically
generated, and cyclicAMI-type patches assume no transformation. For
example (in system/blockMeshDict):
cyclicLeft
{
type cyclic;
neighbourPatch cyclicRight;
faces ((0 1 2 3));
}
cyclicRight
{
type cyclic;
neighbourPatch cyclicLeft;
faces ((4 5 6 7));
}
2) Partial specification. The type of transformation is specified
by the user, as well as the coordinate system if the transform is
rotational. The rotation angle or separation vector is still
automatically generated. This form is useful as the signs of the
angle and separation are opposite on different sides of an interface
and can be difficult to specify correctly. For example:
cyclicLeft
{
type cyclic;
neighbourPatch cyclicRight;
transformType translational;
faces ((0 1 2 3));
}
cyclicRight
{
type cyclic;
neighbourPatch cyclicLeft;
transformType translational;
faces ((4 5 6 7));
}
cyclicAMILeft
{
type cyclicAMI;
neighbourPatch cyclicAMIRight;
transformType rotational;
rotationAxis (0 0 1);
rotationCentre (0.05 -0.01 0);
faces ((8 9 10 11));
}
cyclicAMIRight
{
type cyclicAMI;
neighbourPatch cyclicAMILeft;
transformType rotational;
rotationAxis (0 0 1);
rotationCentre (0.05 -0.01 0);
faces ((12 13 14 15));
}
3) Full specification. All parameters of the transformation are
given. For example:
cyclicLeft
{
type cyclic;
neighbourPatch cyclicRight;
transformType translational;
separaion (-0.01 0 0);
faces ((0 1 2 3));
}
cyclicRight
{
type cyclic;
neighbourPatch cyclicLeft;
transformType translational;
separaion (0.01 0 0);
faces ((4 5 6 7));
}
cyclicAMILeft
{
type cyclicAMI;
neighbourPatch cyclicAMIRight;
transformType rotational;
rotationAxis (0 0 1);
rotationCentre (0.05 -0.01 0);
rotationAngle 60;
faces ((8 9 10 11));
}
cyclicAMIRight
{
type cyclicAMI;
neighbourPatch cyclicAMILeft;
transformType rotational;
rotationAxis (0 0 1);
rotationCentre (0.05 -0.01 0);
rotationAngle 60;
faces ((12 13 14 15));
}
Automatic ordering of faces and points across coupled patches has also
been rewritten, again replacing multiple unsatisfactory implementations.
The new ordering method is more robust on poor meshes as it
geometrically matches only a single face (per contiguous region of the
patch) in order to perform the ordering, and this face is chosen to be
the one with the highest quality. A failure in ordering now only occurs
if the best face in the patch cannot be geometrically matched, whether
as previously the worst face could cause the algorithm to fail.
The oldCyclicPolyPatch has been removed, and the mesh converters which
previously used it now all generate ordered cyclic and baffle patches
directly. This removes the need to run foamUpgradeCyclics after
conversion. In addition the fluent3DMeshToFoam converter now supports
conversion of periodic/shadow pairs to OpenFOAM cyclic patches.
A single transformer object is now maintained within cyclic patches and returned
from a single virtual functions massively simplifying the interface and allowing
for further rationalisation of the calculation of the transformation.
The implementation of the optional non-uniform transformations in coupled
patches was based on transform property lists which could be either length 0 for
no transformation, 1 for uniform transformation or n-faces for non-uniform
transformation. This complexity was maintenance nightmare but kept to support
the hack in the original film implementation to partially work around the
conservation error. Now that film has been re-implemented in fully mass
conservative form this unphysical non-uniform transformation support is no
longer needed and the coupled patch transformations have been completely
refactored to be simpler and more rational with single values for the
transformation properties and boolians to indicate which transformations are
needed.
All of the film transport equations are now formulated with respect to the film
volume fraction in the region cell layer rather than the film thickness which
ensures mass conservation of the film even as it flows over curved surfaces and
around corners. (In the previous formulation the conservation error could be as
large as 15% for a film flowing around a corner.)
The film Courant number is now formulated in terms of the film cell volumetric
flux which avoids the stabilised division by the film thickness and provides a
more reliable estimate for time-step evaluation. As a consequence the film
solution is substantially more robust even though the time-step is now
significantly higher. For film flow dominated problem the simulations now runs
10-30x faster.
The inconsistent extended PISO controls have been replaced by the standard
PIMPLE control system used in all other flow solvers, providing consistent
input, a flexible structure and easier maintenance.
The momentum corrector has been re-formulated to be consistent with the momentum
predictor so the optional PIMPLE outer-corrector loop converges which it did not
previously.
nonuniformTransformCyclic patches and corresponding fields are no longer needed
and have been removed which paves the way for a future rationalisation of the
handling of cyclic transformations in OpenFOAM to improve robustness, usability
and maintainability.
Film sources have been simplified to avoid the need for fictitious boundary
conditions, in particular mappedFixedPushedInternalValueFvPatchField which has
been removed.
Film variables previously appended with an "f" for "film" rather than "face"
have been renamed without the unnecessary and confusing "f" as they are
localised to the film region and hence already directly associated with it.
All film tutorials have been updated to test and demonstrate the developments
and improvements listed above.
Henry G. Weller
CFD Direct Ltd.
and copy assignment operator for classes with a copy constructor
This is often described as the rule of 3 (or rule of 5 in C++11 if move
constructors and assignment operators are also defined) and makes good sense in
ensuring consistency. For classes in which the default bitwise copy constructor
or assignment operator are appropriate these are now specified explicitly using
the "= default" keyword if the other is explicitly defined fulfilling the rule
of 3 without the need to define the body of the function.
Currently these deleted function declarations are still in the private section
of the class declarations but will be moved by hand to the public section over
time as this is too complex to automate reliably.
Replaced all uses of complex Xfer class with C++11 "move" constructors and
assignment operators. Removed the now redundant Xfer class.
This substantial changes improves consistency between OpenFOAM and the C++11 STL
containers and algorithms, reduces memory allocation and copy overhead when
returning containers from functions and simplifies maintenance of the core
libraries significantly.
The base dynamicFvMesh now reads and stores the dynamicMeshDict and motion
solver receive it as a constructor argument.
Also rationalised the motionSolver diffusivity classes in which storing the
faceDiffusivity field provided no advantage; now it is created and returned on
demand.
The sub-loops of the solution control are now named more consistently,
with ambiguously named methods such as finalIter replaced with ones
like finalPimpleIter, so that it is clear which loop they represent.
In addition, the final logic has been improved so that it restores state
after a sub-iteration, and so that sub-iterations can be used on their
own without an outer iteration in effect. Previously, if the
non-orthogonal loop were used outside of a pimple/piso iteration, the
final iteration would not execute with final settings.
Registration occurs when the temporary field is transferred to a non-temporary
field via a constructor or if explicitly transferred to the database via the
regIOobject "store" methods.
