For example the generation term in the k-epsilon turbulence kEpsilon:G is a
temporary field that is specifically named and registered so that it can be
looked-up be the wall-function boundary conditions and requires slightly
different handling compared to normal temporary fields which are not registered.
The tutorials/incompressible/simpleFoam/pitzDaily case now demostrates this
functionality with the addition of
cacheTemporaryObjects
(
kEpsilon:G
);
functions
{
#includeFunc writeObjects(objects = (kEpsilon:G))
}
in controlDict which caches kEpsilon:G and writes it at every write time.
and removed it from equations of state for which it is too inaccurate to be
useful, in particular from perfectFluid which has been superseded by rPolynomial
which is more accurate and naturally support coefficient mixing.
Description
Reciprocal polynomial equation of state for liquids and solids
\f[
1/\rho = C_0 + C_1 T + C_2 T^2 - C_3 p - C_4 p T
\f]
This polynomial for the reciprocal of the density provides a much better fit
than the equivalent polynomial for the density and has the advantage that it
support coefficient mixing to support liquid and solid mixtures in an
efficient manner.
Usage
\table
Property | Description
C | Density polynomial coefficients
\endtable
Example of the specification of the equation of state for pure water:
\verbatim
equationOfState
{
C (0.001278 -2.1055e-06 3.9689e-09 4.3772e-13 -2.0225e-16);
}
\endverbatim
Note: This fit is based on the small amount of data which is freely
available for the range 20-65degC and 1-100bar.
This equation of state is a much better fit for water and other liquids than
perfectFluid and in general polynomials for the reciprocal of the density
converge much faster than polynomials of the density. Currently rPolynomial is
quadratic in the temperature and linear in the pressure which is sufficient for
modest ranges of pressure typically encountered in CFD but could be extended to
higher order in pressure and/temperature if necessary. The other huge advantage
in formulating the equation of state in terms of the reciprocal of the density
is that coefficient mixing is simple.
Given these advantages over the perfectFluid equation of state the libraries and
tutorial cases have all been updated to us rPolynomial rather than perfectFluid
for liquids and water in particular.
Cebeci, T., & Bradshaw, P. (1977).
Momentum transfer in boundary layers.
Washington, DC, Hemisphere Publishing Corp.; New York,
McGraw-Hill Book Co., 1977. 407 p.
The yPlus function object can now take a "phase" keyword which defines
the name of the phase for which to write yPlus. For example, to write
yPlus for a phase named "liquid", the following entry can be used:
yPlus1
{
type yPlus;
libs ("libfieldFunctionObjects.so");
phase liquid;
}
Note that this will only be necessary in Euler-Euler type simulations
where the phases have separate turbulence models. For VoF, the phase
name will not be required.
Patch contributed by Juho Peltola, VTT.
Allows directories to contain included files without FoamFile headers without
generating warning messages from ParaFoam and other post-processing tools.
e.g. given a vol pressure field p
functions
{
// Interpolate the pressure field to the faces
surfacep
{
type surfaceInterpolate;
libs ("libfieldFunctionObjects.so");
fields ((p surfacep));
writeControl none;
}
// Average the surface pressure field over the centre faceZone
#includeFunc faceZoneAverage(name=centre, surfacep)
.
.
.
}
and removed the need for the direct dependency of Ostream on keyType which is
not a primitive IO type and relates specifically to dictionary and not all IO.
to conveniently handle the cases where the particular string type does not
matter, e.g. the string equality comparison in the ifeqEntry dictionary function
entry.
