See GL #1433
Applies corrections to turbulence kinetic energy equation and turbulence
viscosity field for incompressible multiphase flow cases.
Turbulence kinetic energy is over-predicted in VOF solvers at the phase
interface and throughout the water column in nearly-potential flow regions
beneath surface waves.
This fvOption applies corrections based on the references:
Buoyancy source term in turbulence kinetic energy equation:
Devolder, B., Rauwoens, P., and Troch, P. (2017).
Application of a buoyancy-modified k-w SST turbulence model to
simulate wave run-up around a monopile subjected to regular waves
using OpenFOAM.
Coastal Engineering, 125, 81-94.
Correction to turbulence viscosity field:
Larsen, B.E. and Fuhrman, D.R. (2018).
On the over-production of turbulence beneath surface waves in
Reynolds-averaged Navier-Stokes models
J. Fluid Mech, 853, 419-460
Example usage:
multiphaseStabilizedTurbulence1
{
type multiphaseStabilizedTurbulence;
active yes;
multiphaseStabilizedTurbulenceCoeffs
{
// Optional coefficients
lambda2 0.1; // A value of 0 sets the nut correction to 0
Cmu 0.09; // from k-epsilon model
C 1.51; // model coefficient from k-omega model
alpha 1.36; // 1/Prt
}
}
Thanks go to the Turbulence Technical Committee, and the useful discussions
with and code testing by Bjarke Eltard-Larsen and David Fuhrman (Technical
University of Denmark).
- for codedFunctionObject and CodedSource the main code snippets
were not included in the SHA1 calculation, which meant that many
changes would not be noticed and no new library would be compiled.
As a workaround, a dummy 'code' entry could be used solely for the
purposes of generating a SHA1, but this is easily forgotten.
We now allow tracking of the dynamicCodeContext for the coded
objects and append to the SHA1 hasher with specific entries.
This should solve the previous misbehaviour.
We additionally add information about the ordering of the code
sections. Suppose we have a coded function object (all code
segments are optional) with the following:
codeExecute "";
codeWrite #{ Info<< "Called\n"; #};
which we subsequently change to this:
codeExecute #{ Info<< "Called\n"; #};
codeWrite "";
If the code strings are simply concatenated together, the SHA1 hashes
will be identical. We thus 'salt' with their semantic locations,
choosing tags that are unlikely to occur within the code strings
themselves.
- simplify the coded templates with constexpr for the SHA1sum
information.
- Correct the CodedSource to use 'codeConstrain' instead of
'codeSetValue' for consistency with the underlying functions.
- Eg, with surface writers now in surfMesh, there are fewer libraries
depending on conversion and sampling.
COMP: regularize linkage ordering and avoid some implicit linkage (#1238)
- makes the intent clearer and avoids the need for additional
constructor casting. Eg,
labelList(10, Zero) vs. labelList(10, 0)
scalarField(10, Zero) vs. scalarField(10, scalar(0))
vectorField(10, Zero) vs. vectorField(10, vector::zero)
- as part of the cleanup of dictionary access methods (c6520033c9)
made the dictionary class single inheritance from IDLList<entry>.
This eliminates any ambiguities for iterators and allows
for simple use of range-for looping.
Eg,
for (const entry& e : topDict))
{
Info<< "entry:" << e.keyword() << " is dict:" << e.isDict() << nl;
}
vs
forAllConstIter(dictionary, topDict, iter))
{
Info<< "entry:" << iter().keyword()
<< " is dict:" << iter().isDict() << nl;
}
- more dictionary-like methods, enforce keyType::LITERAL for all
lookups to avoid any spurious keyword matching.
- new readEntry, readIfPresent methods
- The get() method replaces the now deprecate lookup() method.
- Deprecate lookupOrFailsafe()
Failsafe behaviour is now an optional parameter for lookupOrDefault,
which makes it easier to tailor behaviour at runtime.
- output of the names is now always flatted without line-breaks.
Thus,
os << flatOutput(someEnumNames.names()) << nl;
os << someEnumNames << nl;
both generate the same output.
- Constructor now uses C-string (const char*) directly instead of
Foam::word in its initializer_list.
- Remove special enum + initializer_list constructor form since
it can create unbounded lookup indices.
- Removd old hasEnum, hasName forms that were provided during initial
transition from NamedEnum.
- Added static_assert on Enum contents to restrict to enum or
integral values. Should not likely be using this class to enumerate
other things since it internally uses an 'int' for its values.
Changed volumeType accordingly to enumerate on its type (enum),
not the class itself.
New name: findObject(), cfindObject()
Old name: lookupObjectPtr()
Return a const pointer or nullptr on failure.
New name: findObject()
Old name: --
Return a non-const pointer or nullptr on failure.
New name: getObjectPtr()
Old name: lookupObjectRefPtr()
Return a non-const pointer or nullptr on failure.
Can be called on a const object and it will perform a
const_cast.
- use these updated names and functionality in more places
NB: The older methods names are deprecated, but continue to be defined.
- use keyType::option enum to consolidate searching options.
These enumeration names should be more intuitive to use
and improve code readability.
Eg, lookupEntry(key, keyType::REGEX);
vs lookupEntry(key, false, true);
or
Eg, lookupEntry(key, keyType::LITERAL_RECURSIVE);
vs lookupEntry(key, true, false);
- new findEntry(), findDict(), findScoped() methods with consolidated
search options for shorter naming and access names more closely
aligned with other components. Behave simliarly to the
methods lookupEntryPtr(), subDictPtr(), lookupScopedEntryPtr(),
respectively. Default search parameters consistent with lookupEntry().
Eg, const entry* e = dict.findEntry(key);
vs const entry* e = dict.lookupEntryPtr(key, false, true);
- added '*' and '->' dereference operators to dictionary searchers.
- use the dictionary 'get' methods instead of readScalar for
additional checking
Unchecked: readScalar(dict.lookup("key"));
Checked: dict.get<scalar>("key");
- In templated classes that also inherit from a dictionary, an additional
'template' keyword will be required. Eg,
this->coeffsDict().template get<scalar>("key");
For this common use case, the predefined getXXX shortcuts may be
useful. Eg,
this->coeffsDict().getScalar("key");
Previously the coordinate system functionality was split between
coordinateSystem and coordinateRotation. The coordinateRotation stored
the rotation tensor and handled all tensor transformations.
The functionality has now been revised and consolidated into the
coordinateSystem classes. The sole purpose of coordinateRotation
is now just to provide a selectable mechanism of how to define the
rotation tensor (eg, axis-angle, euler angles, local axes) for user
input, but after providing the appropriate rotation tensor it has
no further influence on the transformations.
--
The coordinateSystem class now contains an origin and a base rotation
tensor directly and various transformation methods.
- The origin represents the "shift" for a local coordinate system.
- The base rotation tensor represents the "tilt" or orientation
of the local coordinate system in general (eg, for mapping
positions), but may require position-dependent tensors when
transforming vectors and tensors.
For some coordinate systems (currently the cylindrical coordinate system),
the rotation tensor required for rotating a vector or tensor is
position-dependent.
The new coordinateSystem and its derivates (cartesian, cylindrical,
indirect) now provide a uniform() method to define if the rotation
tensor is position dependent/independent.
The coordinateSystem transform and invTransform methods are now
available in two-parameter forms for obtaining position-dependent
rotation tensors. Eg,
... = cs.transform(globalPt, someVector);
In some cases it can be useful to use query uniform() to avoid
storage of redundant values.
if (cs.uniform())
{
vector xx = cs.transform(someVector);
}
else
{
List<vector> xx = cs.transform(manyPoints, someVector);
}
Support transform/invTransform for common data types:
(scalar, vector, sphericalTensor, symmTensor, tensor).
====================
Breaking Changes
====================
- These changes to coordinate systems and rotations may represent
a breaking change for existing user coding.
- Relocating the rotation tensor into coordinateSystem itself means
that the coordinate system 'R()' method now returns the rotation
directly instead of the coordinateRotation. The method name 'R()'
was chosen for consistency with other low-level entities (eg,
quaternion).
The following changes will be needed in coding:
Old: tensor rot = cs.R().R();
New: tensor rot = cs.R();
Old: cs.R().transform(...);
New: cs.transform(...);
Accessing the runTime selectable coordinateRotation
has moved to the rotation() method:
Old: Info<< "Rotation input: " << cs.R() << nl;
New: Info<< "Rotation input: " << cs.rotation() << nl;
- Naming consistency changes may also cause code to break.
Old: transformVector()
New: transformPrincipal()
The old method name transformTensor() now simply becomes transform().
====================
New methods
====================
For operations requiring caching of the coordinate rotations, the
'R()' method can be used with multiple input points:
tensorField rots(cs.R(somePoints));
and later
Foam::transformList(rots, someVectors);
The rotation() method can also be used to change the rotation tensor
via a new coordinateRotation definition (issue #879).
The new methods transformPoint/invTransformPoint provide
transformations with an origin offset using Cartesian for both local
and global points. These can be used to determine the local position
based on the origin/rotation without interpreting it as a r-theta-z
value, for example.
================
Input format
================
- Streamline dictionary input requirements
* The default type is cartesian.
* The default rotation type is the commonly used axes rotation
specification (with e1/e2/3), which is assumed if the 'rotation'
sub-dictionary does not exist.
Example,
Compact specification:
coordinateSystem
{
origin (0 0 0);
e2 (0 1 0);
e3 (0.5 0 0.866025);
}
Full specification (also accepts the longer 'coordinateRotation'
sub-dictionary name):
coordinateSystem
{
type cartesian;
origin (0 0 0);
rotation
{
type axes;
e2 (0 1 0);
e3 (0.5 0 0.866025);
}
}
This simplifies the input for many cases.
- Additional rotation specification 'none' (an identity rotation):
coordinateSystem
{
origin (0 0 0);
rotation { type none; }
}
- Additional rotation specification 'axisAngle', which is similar
to the -rotate-angle option for transforming points (issue #660).
For some cases this can be more intuitive.
For example,
rotation
{
type axisAngle;
axis (0 1 0);
angle 30;
}
vs.
rotation
{
type axes;
e2 (0 1 0);
e3 (0.5 0 0.866025);
}
- shorter names (or older longer names) for the coordinate rotation
specification.
euler EulerRotation
starcd STARCDRotation
axes axesRotation
================
Coding Style
================
- use Foam::coordSystem namespace for categories of coordinate systems
(cartesian, cylindrical, indirect). This reduces potential name
clashes and makes a clearer declaration. Eg,
coordSystem::cartesian csys_;
The older names (eg, cartesianCS, etc) remain available via typedefs.
- added coordinateRotations namespace for better organization and
reduce potential name clashes.
- this provides internal consistency and allows direct use of the
coordinate angle with sin(), cos() functions.
It eliminates potential issues that could otherwise arise from
alternative user input.
Eg, in mixerFvMesh it would have previously been possible to specify
the coordinate system to use degrees or radians, but these units were
not checked when determining the tangential sweep positions.
NOTE: this may represent a breaking change if user coding has been
relying on cylindrical coordinate system in degrees.
- avoids compiler ambiguity when virtual methods such as
IOdictionary::read() exist.
- the method was introduced in 1806, and was thus not yet widely used
- relocate some standard functionality to TimePaths to allow a lighter
means of managing time directories without using the entire Time
mechanism.
- optional enableLibs for Time construction (default is on)
and a corresponding argList::noLibs() and "-no-libs" option
STYLE:
- mark Time::outputTime() as deprecated MAY-2016
- use pre-increment for runTime, although there is no difference in
behaviour or performance.
Specialized variants of the power law porosity and k epsilon turbulence models
developed to simulate atmospheric flow over forested and non-forested complex
terrain.
Class
Foam::powerLawLopesdaCosta
Description
Variant of the power law porosity model with spatially varying
drag coefficient
given by:
\f[
S = -\rho C_d \Sigma |U|^{(C_1 - 1)} U
\f]
where
\vartable
\Sigma | Porosity surface area per unit volume
C_d | Model linear coefficient
C_1 | Model exponent coefficient
\endvartable
Reference:
\verbatim
Costa, J. C. P. L. D. (2007).
Atmospheric flow over forested and non-forested complex terrain.
\endverbatim
Class
Foam::RASModels::kEpsilonLopesdaCosta
Description
Variant of the standard k-epsilon turbulence model with additional source
terms to handle the changes in turbulence in porous regions represented by
the powerLawLopesdaCosta porosity model.
Reference:
\verbatim
Costa, J. C. P. L. D. (2007).
Atmospheric flow over forested and non-forested complex terrain.
\endverbatim
The default model coefficients are
\verbatim
kEpsilonLopesdaCostaCoeffs
{
Cmu 0.09;
C1 1.44;
C2 1.92;
sigmak 1.0;
sigmaEps 1.3;
}
\endverbatim
Tutorial case to follow.
- both autoPtr and tmp are defined with an implicit construct from
nullptr (but with explicit construct from a pointer to null).
Thus is it safe to use 'nullptr' when returning an empty autoPtr or tmp.
- when constructing dimensioned fields that are to be zero-initialized,
it is preferrable to use a form such as
dimensionedScalar(dims, Zero)
dimensionedVector(dims, Zero)
rather than
dimensionedScalar("0", dims, 0)
dimensionedVector("zero", dims, vector::zero)
This reduces clutter and also avoids any suggestion that the name of
the dimensioned quantity has any influence on the field's name.
An even shorter version is possible. Eg,
dimensionedScalar(dims)
but reduces the clarity of meaning.
- NB: UniformDimensionedField is an exception to these style changes
since it does use the name of the dimensioned type (instead of the
regIOobject).
- in many cases can just use lookupOrDefault("key", bool) instead of
lookupOrDefault<bool> or lookupOrDefault<Switch> since reading a
bool from an Istream uses the Switch(Istream&) anyhow
STYLE: relocated Switch string names into file-local scope
