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.
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.
MULES no longer synchronises the limiter field using syncTools. Surface
boundary field synchronisation is now done with a surface-field-specific
communication procedure that should result in scaling benefits relative
to syncTools. This change also means that the limiter does not need to
be continuous face field which is then sliced; it can be a standard
surface field.
Description
Evolves a passive scalar transport equation.
- To specify the field name set the \c field entry
- To employ the same numerical schemes as another field set
the \c schemesField entry,
- The \c diffusivity entry can be set to \c none, \c constant, \c viscosity
- A constant diffusivity is specified with the \c D entry,
- If a momentum transport model is available and the \c viscosity
diffusivety option specified an effective diffusivity may be constructed
from the laminar and turbulent viscosities using the diffusivity
coefficients \c alphal and \c alphat:
\verbatim
D = alphal*nu + alphat*nut
\endverbatim
Example:
\verbatim
#includeFunc scalarTransport(T, alphaD=1, alphaDt=1)
\endverbatim
For incompressible flow the passive scalar may optionally be solved with the
MULES limiter and sub-cycling or semi-implicit in order to maintain
boundedness, particularly if a compressive, PLIC or MPLIC convection
scheme is used.
Example:
\verbatim
#includeFunc scalarTransport(tracer, diffusion=none)
with scheme specification:
div(phi,tracer) Gauss interfaceCompression vanLeer 1;
and solver specification:
tracer
{
nCorr 1;
nSubCycles 3;
MULESCorr no;
nLimiterIter 5;
applyPrevCorr yes;
solver smoothSolver;
smoother symGaussSeidel;
tolerance 1e-8;
relTol 0;
diffusion
{
solver smoothSolver;
smoother symGaussSeidel;
tolerance 1e-8;
relTol 0;
}
}
\endverbatim
With this change each functionObject provides the list of fields required so
that the postProcess utility can pre-load them before executing the list of
functionObjects. This provides a more convenient interface than using the
-field or -fields command-line options to postProcess which are now redundant.
replacing the virtual functions overridden in engineTime.
Now the userTime conversion function in Time is specified in system/controlDict
such that the solver as well as all pre- and post-processing tools also operate
correctly with the chosen user-time.
For example the user-time and rpm in the tutorials/combustion/XiEngineFoam/kivaTest case are
now specified in system/controlDict:
userTime
{
type engine;
rpm 1500;
}
The default specification is real-time:
userTime
{
type real;
}
but this entry can be omitted as the real-time class is instantiated
automatically if the userTime entry is not present in system/controlDict.
The temperature equation in compressibleInterFoam is derived from the phase
total internal energy equations including the kinetic energy source terms.
While this formulation handles pressure loss more accurately the kinetic energy
source terms can cause numerical problems and more likely to induce negative
temperatures in regions where the pressure drops rapidly. For such cases it may
be beneficial to solve a temperature equation derived from the phase internal
energy equations, i.e. without the kinetic energy source terms which is now
selectable by setting the optional totalInternalEnergy entry in
constant/phaseProperties to false:
totalInternalEnergy false;
When this entry is omitted the total energy form is used providing
backward-compatibility.
Mesh motion and topology change are now combinable run-time selectable options
within fvMesh, replacing the restrictive dynamicFvMesh which supported only
motion OR topology change.
All solvers which instantiated a dynamicFvMesh now instantiate an fvMesh which
reads the optional constant/dynamicFvMeshDict to construct an fvMeshMover and/or
an fvMeshTopoChanger. These two are specified within the optional mover and
topoChanger sub-dictionaries of dynamicFvMeshDict.
When the fvMesh is updated the fvMeshTopoChanger is first executed which can
change the mesh topology in anyway, adding or removing points as required, for
example for automatic mesh refinement/unrefinement, and all registered fields
are mapped onto the updated mesh. The fvMeshMover is then executed which moved
the points only and calculates the cell volume change and corresponding
mesh-fluxes for conservative moving mesh transport. If multiple topological
changes or movements are required these would be combined into special
fvMeshMovers and fvMeshTopoChangers which handle the processing of a list of
changes, e.g. solidBodyMotionFunctions:multiMotion.
The tutorials/multiphase/interFoam/laminar/sloshingTank3D3DoF case has been
updated to demonstrate this new functionality by combining solid-body motion
with mesh refinement/unrefinement:
/*--------------------------------*- C++ -*----------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Version: dev
\\/ M anipulation |
\*---------------------------------------------------------------------------*/
FoamFile
{
format ascii;
class dictionary;
location "constant";
object dynamicMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
mover
{
type motionSolver;
libs ("libfvMeshMovers.so" "libfvMotionSolvers.so");
motionSolver solidBody;
solidBodyMotionFunction SDA;
CofG (0 0 0);
lamda 50;
rollAmax 0.2;
rollAmin 0.1;
heaveA 4;
swayA 2.4;
Q 2;
Tp 14;
Tpn 12;
dTi 0.06;
dTp -0.001;
}
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)
(meshPhi_0 none)
(ghf none)
);
// Write the refinement level as a volScalarField
dumpLevel true;
}
// ************************************************************************* //
Note that currently this is the only working combination of mesh-motion with
topology change within the new framework and further development is required to
update the set of topology changers so that topology changes with mapping are
separated from the mesh-motion so that they can be combined with any of the
other movements or topology changes in any manner.
All of the solvers and tutorials have been updated to use the new form of
dynamicMeshDict but backward-compatibility was not practical due to the complete
reorganisation of the mesh change structure.
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.
Both AMIMethod and mapNearestMethod are run-time selectable using the standard
OpenFOAM constructor tables, they do not need a separate enumeration-based
selection method which requires duplicate constructors and a lot of other
clutter.
used to check the existence of and open an object file, read and check the
header without constructing the object.
'typeIOobject' operates in an equivalent and consistent manner to 'regIOobject'
but the type information is provided by the template argument rather than via
virtual functions for which the derived object would need to be constructed,
which is the case for 'regIOobject'.
'typeIOobject' replaces the previous separate functions 'typeHeaderOk' and
'typeFilePath' with a single consistent interface.
now all path functions in 'IOobject' are either templated on the type or require a
'globalFile' argument to specify if the type is case global e.g. 'IOdictionary' or
decomposed in parallel, e.g. almost everything else.
The 'global()' and 'globalFile()' virtual functions are now in 'regIOobject'
abstract base-class and overridden as required by derived classes. The path
functions using 'global()' and 'globalFile()' to differentiate between global
and processor local objects are now also in 'regIOobject' rather than 'IOobject'
to ensure the path returned is absolutely consistent with the type.
Unfortunately there is still potential for unexpected IO behaviour inconsistent
with the global/local nature of the type due to the 'fileOperation' classes
searching the processor directory for case global objects before searching the
case directory. This approach appears to be a work-around for incomplete
integration with and rationalisation of 'IOobject' but with the changes above it
is no longer necessary. Unfortunately this "up" searching is baked-in at a low
level and mixed-up with various complex ways to pick the processor directory
name out of the object path and will take some unravelling but this work will
undertaken as time allows.
Provided for use with mixture turbulence models in interFoam and
compressibleInterFoam.
Class
Foam::fv::VoFTurbulenceDamping
Description
Free-surface turbulence damping function
Adds an extra source term to the mixture or phase epsilon or omega
equation to reduce turbulence generated near a free-surface. The
implementation is based on
Reference:
\verbatim
Frederix, E. M. A., Mathur, A., Dovizio, D., Geurts, B. J.,
& Komen, E. M. J. (2018).
Reynolds-averaged modeling of turbulence damping
near a large-scale interface in two-phase flow.
Nuclear engineering and design, 333, 122-130.
\endverbatim
but with an improved formulation for the coefficient \c A appropriate for
unstructured meshes including those with split-cell refinement patterns.
However the dimensioned length-scale coefficient \c delta remains and must
be set appropriatly for the case by performing test runs and comparing with
known results. Clearly this model is far from general and more research is
needed in order that \c delta can be obtained directly from the interface
flow and turbulence conditions.
Usage
Example usage:
\verbatim
VoFTurbulenceDamping
{
type VoFTurbulenceDamping;
libs ("libVoFTurbulenceDamping.so");
// Interface turbulence damping length scale
// This is a required input as described in section 3.3 of the paper
delta 1e-4;
// phase water; // Optional phase name
}
\endverbatim
to provide a single consistent code and user interface to the specification of
physical properties in both single-phase and multi-phase solvers. This redesign
simplifies usage and reduces code duplication in run-time selectable solver
options such as 'functionObjects' and 'fvModels'.
* physicalProperties
Single abstract base-class for all fluid and solid physical property classes.
Physical properties for a single fluid or solid within a region are now read
from the 'constant/<region>/physicalProperties' dictionary.
Physical properties for a phase fluid or solid within a region are now read
from the 'constant/<region>/physicalProperties.<phase>' dictionary.
This replaces the previous inconsistent naming convention of
'transportProperties' for incompressible solvers and
'thermophysicalProperties' for compressible solvers.
Backward-compatibility is provided by the solvers reading
'thermophysicalProperties' or 'transportProperties' if the
'physicalProperties' dictionary does not exist.
* phaseProperties
All multi-phase solvers (VoF and Euler-Euler) now read the list of phases and
interfacial models and coefficients from the
'constant/<region>/phaseProperties' dictionary.
Backward-compatibility is provided by the solvers reading
'thermophysicalProperties' or 'transportProperties' if the 'phaseProperties'
dictionary does not exist. For incompressible VoF solvers the
'transportProperties' is automatically upgraded to 'phaseProperties' and the
two 'physicalProperties.<phase>' dictionary for the phase properties.
* viscosity
Abstract base-class (interface) for all fluids.
Having a single interface for the viscosity of all types of fluids facilitated
a substantial simplification of the 'momentumTransport' library, avoiding the
need for a layer of templating and providing total consistency between
incompressible/compressible and single-phase/multi-phase laminar, RAS and LES
momentum transport models. This allows the generalised Newtonian viscosity
models to be used in the same form within laminar as well as RAS and LES
momentum transport closures in any solver. Strain-rate dependent viscosity
modelling is particularly useful with low-Reynolds number turbulence closures
for non-Newtonian fluids where the effect of bulk shear near the walls on the
viscosity is a dominant effect. Within this framework it would also be
possible to implement generalised Newtonian models dependent on turbulent as
well as mean strain-rate if suitable model formulations are available.
* visosityModel
Run-time selectable Newtonian viscosity model for incompressible fluids
providing the 'viscosity' interface for 'momentumTransport' models.
Currently a 'constant' Newtonian viscosity model is provided but the structure
supports more complex functions of time, space and fields registered to the
region database.
Strain-rate dependent non-Newtonian viscosity models have been removed from
this level and handled in a more general way within the 'momentumTransport'
library, see section 'viscosity' above.
The 'constant' viscosity model is selected in the 'physicalProperties'
dictionary by
viscosityModel constant;
which is equivalent to the previous entry in the 'transportProperties'
dictionary
transportModel Newtonian;
but backward-compatibility is provided for both the keyword and model
type.
* thermophysicalModels
To avoid propagating the unnecessary constructors from 'dictionary' into the
new 'physicalProperties' abstract base-class this entire structure has been
removed from the 'thermophysicalModels' library. The only use for this
constructor was in 'thermalBaffle' which now reads the 'physicalProperties'
dictionary from the baffle region directory which is far simpler and more
consistent and significantly reduces the amount of constructor code in the
'thermophysicalModels' library.
* compressibleInterFoam
The creation of the 'viscosity' interface for the 'momentumTransport' models
allows the complex 'twoPhaseMixtureThermo' derived from 'rhoThermo' to be
replaced with the much simpler 'compressibleTwoPhaseMixture' derived from the
'viscosity' interface, avoiding the myriad of unused thermodynamic functions
required by 'rhoThermo' to be defined for the mixture.
Same for 'compressibleMultiphaseMixture' in 'compressibleMultiphaseInterFoam'.
This is a significant improvement in code and input consistency, simplifying
maintenance and further development as well as enhancing usability.
Henry G. Weller
CFD Direct Ltd.
and only needed if there is a name clash between entries in the source
specification and the set specification, e.g. "name":
{
name rotorCells;
type cellSet;
action new;
source zoneToCell;
sourceInfo
{
name cylinder;
}
}
topoSet is a more flexible and extensible replacement for setSet using standard
OpenFOAM dictionary input format rather than the limited command-line input
format developed specifically for setSet. This replacement allows for the
removal of a significant amount of code simplifying maintenance and the addition
of more topoSet sources.
Settings for the particleTracks utility are now specified in
system/particleTracksDict. Correspondingly, settings for
steadyParticleTracks are now specified in
system/steadyParticleTracksDict.
