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.
with optional specification of the mark/space ratio
Templated square-wave function with support for an offset level.
\f[
a square(f (t - t_0)) s + l
\f]
where
\f$ square(t) \f$ is the square-wave function in range \f$ [-1, 1] \f$
with a mark/space ratio of \f$ r \f$
\vartable
symbol | Description | Data type | Default
a | Amplitude | Function1<scalar> |
f | Frequency [1/s] | Function1<scalar> |
s | Type scale factor | Function1<Type> |
l | Type offset level | Function1<Type> |
t_0 | Start time [s] | scalar | 0
r | mark/space ratio | scalar | 1
t | Time [s] | scalar
\endvartable
Example for a scalar:
\verbatim
<entryName> square;
<entryName>Coeffs
{
frequency 10;
amplitude 0.1;
scale 2e-6;
level 2e-6;
}
\endverbatim
etc/config.sh and etc/config.csh
This structure is more convenient to add support for other shells, e.g. zsh, fish etc.
Resolves feature request to simplify support for other shells in
http://www.openfoam.org/mantisbt/view.php?id=1232
To see the different behavior of flow through and around the blockage
change D in constant/fvOptions:
// D 100; // Very little blockage
// D 200; // Some blockage but steady flow
// D 500; // Slight waviness in the far wake
D 1000; // Fully shedding behavior
Templated sine function with support for an offset level.
\f[
a sin(2 \pi f (t - t_0)) s + l
\f]
where
\vartable
symbol | Description | Data type
a | Amplitude | Function1<scalar>
f | Frequency [1/s] | Function1<scalar>
s | Type scale factor | Function1<Type>
l | Type offset level | Function1<Type>
t_0 | Start time [s] | scalar
t | Time [s] | scalar
\endvartable
Function1 is an abstract base-class of run-time selectable unary
functions which may be composed of other Function1's allowing the user
to specify complex functions of a single scalar variable, e.g. time.
The implementations need not be a simple or continuous functions;
interpolated tables and polynomials are also supported. In fact form of
mapping between a single scalar input and a single primitive type output
is supportable.
The primary application of Function1 is in time-varying boundary
conditions, it also used for other functions of time, e.g. injected mass
is spray simulations but is not limited to functions of time.
Description
Templated sine function with support for an offset level.
\f[
a sin(2 \pi f (t - t_0)) s + l
\f]
where
\vartable
a | Amplitude
f | Frequency [1/s]
s | Type scale factor
l | Type offset level
t_0 | Start time [s]
t | Time [s]
\endvartable
Example for a scalar:
\verbatim
<entryName> sine;
<entryName>Coeffs
{
frequency 10;
amplitude 0.1;
scale 2e-6;
level 2e-6;
}
\endverbatim
Example for a vector:
\verbatim
<entryName> sine;
<entryName>Coeffs
{
frequency 10;
amplitude 1;
scale (1 0.1 0);
level (10 1 0);
}
\endverbatim
PV4FoamReaders: Updated to build with ParaView-5.0.0
paraFoam: Updated to load PV4FoamReaders for ParaView-5.0.0
Currently this is experimental but if it becomes clear that ParaView-4
and ParaView-5 are and will remain consistent with respect to readers
the plan is to rename
PV4 -> PV
or
PV4 -> PV45 if it is assumed that PV6 may need to be different.
