for consistency with fvModels and fvConstraints, to simplify code and case
maintenance and to avoid the potentially complex functions entries being
unnecessarily parsed by utilities for which functionObject evaluation is
disabled.
The functions entry in controlDict is still read if the functions file is not
present for backward-compatibility, but it is advisable to migrate cases to use
the new functions file.
The fact that these names refer to constraints is clear in context, so
the name does not need to contain 'Constraint'.
Having 'Constraint' in the name is a historic convention that dates back
to when fvConstraints and fvModels were combined in a single fvOptions
interface. In this interface, disambiguation between sources and
constraints was necessary.
This change has been applied to the 'fixedValue' and 'fixedTemperature'
constraints, which were formerly named 'fixedValueConstraint' and
'fixedTemperatureConstraint', respectively.
The old names are still available for backwards compatibility.
Description
Calculates and applies the random OU (Ornstein-Uhlenbeck) process force to
the momentum equation for direct numerical simulation of boxes of isotropic
turbulence.
The energy spectrum is calculated and written at write-times which is
particularly useful to test and compare LES SGS models.
Note
This random OU process force uses a FFT to generate the force field which
is not currently parallelised. Also the mesh the FFT is applied to must
be isotropic and have a power of 2 cells in each direction.
Usage
Example usage:
\verbatim
OUForce
{
type OUForce;
libs ("librandomProcesses.so");
sigma 0.090295;
alpha 0.81532;
kUpper 10;
kLower 7;
}
\endverbatim
The tutorials/incompressibleFluid/boxTurb16 tutorial case is an updated version
of the original tutorials/legacy/incompressible/dnsFoam/boxTurb16 case,
demonstrating the use of the OUForce fvModel with the incompressibleFluid solver
module to replicate the behaviour of the legacy dnsFoam solver application.
setFormat no longer defaults to the value of graphFormat optionally set in
controlDict and must be set in the functionObject dictionary.
boundaryFoam, financialFoam and pdfPlot still require a graphFormat entry in
controlDict but this is now read directly rather than by Time.
This avoids potential hidden run-time errors caused by solvers running with
boundary conditions which are not fully specified. Note that "null-constructor"
here means the constructor from patch and internal field only, no data is
provided.
Constraint and simple BCs such as 'calculated', 'zeroGradient' and others which
do not require user input to fully specify their operation remain on the
null-constructor table for the construction of fields with for example all
'calculated' or all 'zeroGradient' BCs.
A special version of the 'inletOutlet' fvPatchField named 'zeroInletOutlet' has
been added in which the inlet value is hard-coded to zero which allows this BC
to be included on the null-constructor table. This is useful for the 'age'
functionObject to avoid the need to provide the 'age' volScalarField at time 0
unless special inlet or outlet BCs are required. Also for isothermalFilm in
which the 'alpha' field is created automatically from the 'delta' field if it is
not present and can inherit 'zeroInletOutlet' from 'delta' if appropriate. If a
specific 'inletValue' is require or other more complex BCs then the 'alpha'
field file must be provided to specify these BCs as before.
Following this improvement it will now be possible to remove the
null-constructors from all fvPatchFields not added to the null-constructor
table, which is most of them, thus reducing the amount of code and maintenance
overhead and making easier and more obvious to write new fvPatchField types.
