These new names are more consistent and logical because:
primitiveField():
primitiveFieldRef():
Provides low-level access to the Field<Type> (primitive field)
without dimension or mesh-consistency checking. This should only be
used in the low-level functions where dimensional consistency is
ensured by careful programming and computational efficiency is
paramount.
internalField():
internalFieldRef():
Provides access to the DimensionedField<Type, GeoMesh> of values on
the internal mesh-type for which the GeometricField is defined and
supports dimension and checking and mesh-consistency checking.
In order to simplify expressions involving dimensioned internal field it
is preferable to use a simpler access convention. Given that
GeometricField is derived from DimensionedField it is simply a matter of
de-referencing this underlying type unlike the boundary field which is
peripheral information. For consistency with the new convention in
"tmp" "dimensionedInteralFieldRef()" has been renamed "ref()".
Non-const access to the internal field now obtained from a specifically
named access function consistent with the new names for non-canst access
to the boundary field boundaryFieldRef() and dimensioned internal field
dimensionedInternalFieldRef().
See also commit a4e2afa4b3
When the GeometricBoundaryField template class was originally written it
was a separate class in the Foam namespace rather than a sub-class of
GeometricField as it is now. Without loss of clarity and simplifying
code which access the boundary field of GeometricFields it is better
that GeometricBoundaryField be renamed Boundary for consistency with the
new naming convention for the type of the dimensioned internal field:
Internal, see commit a25a449c9e
This is a very simple text substitution change which can be applied to
any code which compiles with the OpenFOAM-dev libraries.
Given that the type of the dimensioned internal field is encapsulated in
the GeometricField class the name need not include "Field"; the type
name is "Internal" so
volScalarField::DimensionedInternalField -> volScalarField::Internal
In addition to the ".dimensionedInternalField()" access function the
simpler "()" de-reference operator is also provided to greatly simplify
FV equation source term expressions which need not evaluate boundary
conditions. To demonstrate this kEpsilon.C has been updated to use
dimensioned internal field expressions in the k and epsilon equation
source terms.
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1938
Because C++ does not support overloading based on the return-type there
is a problem defining both const and non-const member functions which
are resolved based on the const-ness of the object for which they are
called rather than the intent of the programmer declared via the
const-ness of the returned type. The issue for the "boundaryField()"
member function is that the non-const version increments the
event-counter and checks the state of the stored old-time fields in case
the returned value is altered whereas the const version has no
side-effects and simply returns the reference. If the the non-const
function is called within the patch-loop the event-counter may overflow.
To resolve this it in necessary to avoid calling the non-const form of
"boundaryField()" if the results is not altered and cache the reference
outside the patch-loop when mutation of the patch fields is needed.
The most straight forward way of resolving this problem is to name the
const and non-const forms of the member functions differently e.g. the
non-const form could be named:
mutableBoundaryField()
mutBoundaryField()
nonConstBoundaryField()
boundaryFieldRef()
Given that in C++ a reference is non-const unless specified as const:
"T&" vs "const T&" the logical convention would be
boundaryFieldRef()
boundaryFieldConstRef()
and given that the const form which is more commonly used is it could
simply be named "boundaryField()" then the logical convention is
GeometricBoundaryField& boundaryFieldRef();
inline const GeometricBoundaryField& boundaryField() const;
This is also consistent with the new "tmp" class for which non-const
access to the stored object is obtained using the ".ref()" member function.
This new convention for non-const access to the components of
GeometricField will be applied to "dimensionedInternalField()" and "internalField()" in the
future, i.e. "dimensionedInternalFieldRef()" and "internalFieldRef()".
Also added the new prghTotalHydrostaticPressure p_rgh BC which uses the
hydrostatic pressure field as the reference state for the far-field
which provides much more accurate entrainment is large open domains
typical of many fire simulations.
The hydrostatic field solution is controlled by the optional entries in
the fvSolution.PIMPLE dictionary, e.g.
hydrostaticInitialization yes;
nHydrostaticCorrectors 5;
and the solver must also be specified for the hydrostatic p_rgh field
ph_rgh e.g.
ph_rgh
{
$p_rgh;
}
Suitable boundary conditions for ph_rgh cannot always be derived from
those for p_rgh and so the ph_rgh is read to provide them.
To avoid accuracy issues with IO, restart and post-processing the p_rgh
and ph_rgh the option to specify a suitable reference pressure is
provided via the optional pRef file in the constant directory, e.g.
dimensions [1 -1 -2 0 0 0 0];
value 101325;
which is used in the relationship between p_rgh and p:
p = p_rgh + rho*gh + pRef;
Note that if pRef is specified all pressure BC specifications in the
p_rgh and ph_rgh files are relative to the reference to avoid round-off
errors.
For examples of suitable BCs for p_rgh and ph_rgh for a range of
fireFoam cases please study the tutorials in
tutorials/combustion/fireFoam/les which have all been updated.
Henry G. Weller
CFD Direct Ltd.
e.g. (fvc::interpolate(HbyA) & mesh.Sf()) -> fvc::flux(HbyA)
This removes the need to create an intermediate face-vector field when
computing fluxes which is more efficient, reduces the peak storage and
improved cache coherency in addition to providing a simpler and cleaner
API.
The deprecated non-const tmp functionality is now on the compiler switch
NON_CONST_TMP which can be enabled by adding -DNON_CONST_TMP to EXE_INC
in the Make/options file. However, it is recommended to upgrade all
code to the new safer tmp by using the '.ref()' member function rather
than the non-const '()' dereference operator when non-const access to
the temporary object is required.
Please report any problems on Mantis.
Henry G. Weller
CFD Direct.
To be used instead of zeroGradientFvPatchField for temporary fields for
which zero-gradient extrapolation is use to evaluate the boundary field
but avoiding fields derived from temporary field using field algebra
inheriting the zeroGradient boundary condition by the reuse of the
temporary field storage.
zeroGradientFvPatchField should not be used as the default patch field
for any temporary fields and should be avoided for non-temporary fields
except where it is clearly appropriate;
extrapolatedCalculatedFvPatchField and calculatedFvPatchField are
generally more suitable defaults depending on the manner in which the
boundary values are specified or evaluated.
The entire OpenFOAM-dev code-base has been updated following the above
recommendations.
Henry G. Weller
CFD Direct
The boundary conditions of HbyA are now constrained by the new "constrainHbyA"
function which applies the velocity boundary values for patches for which the
velocity cannot be modified by assignment and pressure extrapolation is
not specified via the new
"fixedFluxExtrapolatedPressureFvPatchScalarField".
The new function "constrainPressure" sets the pressure gradient
appropriately for "fixedFluxPressureFvPatchScalarField" and
"fixedFluxExtrapolatedPressureFvPatchScalarField" boundary conditions to
ensure the evaluated flux corresponds to the known velocity values at
the boundary.
The "fixedFluxPressureFvPatchScalarField" boundary condition operates
exactly as before, ensuring the correct flux at fixed-flux boundaries by
compensating for the body forces (gravity in particular) with the
pressure gradient.
The new "fixedFluxExtrapolatedPressureFvPatchScalarField" boundary
condition may be used for cases with or without body-forces to set the
pressure gradient to compensate not only for the body-force but also the
extrapolated "HbyA" which provides a second-order boundary condition for
pressure. This is useful for a range a problems including impinging
flow, extrapolated inlet conditions with body-forces or for highly
viscous flows, pressure-induced separation etc. To test this boundary
condition at walls in the motorBike tutorial case set
lowerWall
{
type fixedFluxExtrapolatedPressure;
}
motorBikeGroup
{
type fixedFluxExtrapolatedPressure;
}
Currently the new extrapolated pressure boundary condition is supported
for all incompressible and sub-sonic compressible solvers except those
providing implicit and tensorial porosity support. The approach will be
extended to cover these solvers and options in the future.
Note: the extrapolated pressure boundary condition is experimental and
requires further testing to assess the range of applicability,
stability, accuracy etc.
Henry G. Weller
CFD Direct Ltd.
fvOptions are transferred to the database on construction using
fv::options::New which returns a reference. The same function can be
use for construction and lookup so that fvOptions are now entirely
demand-driven.
The abstract base-classes for fvOptions now reside in the finiteVolume
library simplifying compilation and linkage. The concrete
implementations of fvOptions are still in the single monolithic
fvOptions library but in the future this will be separated into smaller
libraries based on application area which may be linked at run-time in
the same manner as functionObjects.
Provides run-time selection of buoyancy sources for compressible solvers
Replaces the built-in buoyancy sources in XiFoam, reactingFoam and
rhoReactingFoam.
e.g. in constant/fvOptions specify
momentumSource
{
type buoyancyForce;
buoyancyForceCoeffs
{
fieldNames (U);
}
}
and optionally specify the buoyancy energy source in the enthalpy
equation:
energySource
{
type buoyancyEnergy;
buoyancyEnergyCoeffs
{
fieldNames (h);
}
}
or internal energy equation
energySource
{
type buoyancyEnergy;
buoyancyEnergyCoeffs
{
fieldNames (e);
}
}
fvOptions does not have the appropriate structure to support MRF as it
is based on option selection by user-specified fields whereas MRF MUST
be applied to all velocity fields in the particular solver. A
consequence of the particular design choices in fvOptions made it
difficult to support MRF for multiphase and it is easier to support
frame-related and field related options separately.
Currently the MRF functionality provided supports only rotations but
the structure will be generalized to support other frame motions
including linear acceleration, SRF rotation and 6DoF which will be
run-time selectable.
