The writeEntry form is now defined and used consistently throughout OpenFOAM
making it easier to use and extend, particularly to support binary IO of complex
dictionary entries.
In order to increase the flexibility of the wave library, the mean flow
handling has been removed from the waveSuperposition class. This makes
waveSuperposition work purely in terms of perturbations to a mean
background flow.
The input has also been split, with waves now defined as region-wide
settings in constant/waveProperties. The mean flow parameters are sill
defined by the boundary conditions.
The new format of the velocity boundary is much simpler. Only a mean
flow velocity is required.
In 0/U:
boundaryField
{
inlet
{
type waveVelocity;
UMean (2 0 0);
}
// etc ...
}
Other wave boundary conditions have not changed.
The constant/waveProperties file contains the wave model selections and
the settings to define the associated coordinate system and scaling
functions:
In constant/waveProperties:
origin (0 0 0);
direction (1 0 0);
waves
(
Airy
{
length 300;
amplitude 2.5;
phase 0;
angle 0;
}
);
scale table ((1200 1) (1800 0));
crossScale constant 1;
setWaves has been changed to use a system/setWavesDict file rather than
relying on command-line arguments. It also now requires a mean velocity
to be specified in order to prevent ambiguities associated with multiple
inlet patches. An example is shown below:
In system/setWavesDict:
alpha alpha.water;
U U;
liquid true;
UMean (1 0 0);
In early versions of OpenFOAM the scalar limits were simple macro replacements and the
names were capitalized to indicate this. The scalar limits are now static
constants which is a huge improvement on the use of macros and for consistency
the names have been changed to camel-case to indicate this and improve
readability of the code:
GREAT -> great
ROOTGREAT -> rootGreat
VGREAT -> vGreat
ROOTVGREAT -> rootVGreat
SMALL -> small
ROOTSMALL -> rootSmall
VSMALL -> vSmall
ROOTVSMALL -> rootVSmall
The original capitalized are still currently supported but their use is
deprecated.
"pos" now returns 1 if the argument is greater than 0, otherwise it returns 0.
This is consistent with the common mathematical definition of the "pos" function:
https://en.wikipedia.org/wiki/Sign_(mathematics)
However the previous implementation in which 1 was also returned for a 0
argument is useful in many situations so the "pos0" has been added which returns
1 if the argument is greater or equal to 0. Additionally the "neg0" has been
added which returns 1 if if the argument is less than or equal to 0.
This addition allows for theoretical wave models to be utilised for
initialisation and as boundary conditions. Multiple models can be used
simultaneously, each with differing phases and orientations. If multiple
models are used the shapes and velocities are superimposed.
The wave models are specified in the velocity boundary condition. The
phase fraction boundary condition and the set utility both look up the
velocity condition in order to access the wave model. A velocity
boundary may be specified as follows:
inlet
{
type waveVelocity;
origin (0 0 0);
direction (1 0 0);
speed 2;
waves
(
Airy
{
length 300;
amplitude 2.5;
depth 150;
phase 0;
angle 0;
}
);
scale table ((1200 1) (1800 0));
crossScale constant 1;
}
The alpha boundary only requires the type, unless the name of the
velocity field is non-standard, in which case a "U" entry will also be
needed. The setWaves utility does not require a dictionary file; non-
standard field names can be specified as command-line arguments.
Wave models currently available are Airy (1st order) and Stokes2 (second
order). If a depth is specified, and it is not too large, then shallow
terms will be included, otherwise the models assume that the liquid is
deep.
This work was supported by Jan Kaufmann and Jan Oberhagemann at DNV GL.
