# Workflow guidelines¶

Here the suggested workflows for using eddylicious in conduction with various solvers are presented. Basically, whatever solver is used, the following steps have to be performed.

• Specifying the geometry of the inlet for eddylicious.
• Choosing an output format that is compatible with the used solver.
• Generating the inflow fields by running the python script associated with the chosen inflow generation method.
• Setting up the solver to read in boundary data from the hard drive.

## Using eddylicious with OpenFOAM¶

Important

This offering is not approved or endorsed by OpenCFD Limited, producer and distributor of the OpenFOAM software and owner of the OPENFOAM® and OpenCFD® trade marks.

### Specifying the geometry of the inlet¶

Specifying the geometry boils down to producing the list of face centres located at the inlet boundary. The coordinates of the face centres can be used using the sample utility shipped with OpenFOAM.

In the system/sampleDict file, create a sampling surface with the type patch, and specify the inlet patch as the basis for the surface. It is better to turn off triangulation to preserve the original geometry. Choose foamFile as the write format for surfaces.

Even though we are only interested in the geometry, a field for sampling has to be chosen. Any field can be chosen, besides for the velocity field U. This is because the sample utility will attempt to read in the field, and, since we didn’t generate it yet, the field-values simply don’t exist yet.

A sampleDict for a case with the inlet patch named inlet might look something like this.

*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.3.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
version     2.0;
format      ascii;
class       dictionary;
object      sampleDict;
}
surfaceFormat foamFile;

fields
(
p
);

surfaces
(
inlet
{
type patch;
patches (inlet);
interpolate false;
triangulate false;
}

);


The produced file can be read using the foamFile inflow geometry reader. The path to the faceCenters file should also be provided. This is done by adding the following lines to the configuration file for the inflow generation script.

inflowGeometryReader    foamFile
inflowGeometryPath      "/path/to/faceCenters/file"


### Reading the inflow fields from OpenFOAM¶

OpenFOAM has a special boundary condition that allows reading boundary data from a file, it is called timeVaryingMappedFixedValue. A tutorial, which takes advantage of this boundary condition, is shipped with OpenFOAM. It can be found under tutorials/incompressible/simpleFoam/pitzDailyExptInlet/.

The boundary condition is quite flexible. If needed, interpolation in space will be used to obtain the vales at the face centres from the values at the provided points. Linear interpolation in time is also supported.

Let inlet be the name of the patch for which the inflow fields are generated. Then the following entry should be found in the U file.

inlet
{
type            timeVaryingMappedFixedValue;
offset          (0 0 0);
setAverage      off;
perturb         0;
}


Setting perturb to 0 is important, since this option perturbs the location of the points.

In order to generate the inflow fields the OpenFOAM native format should be used for writing the velocity fields to the hard drive.

Note that, for a large time-span, the amount of files written to disk become extremely large. To rectify this issue, a modified version of timeVaryingMappedFixedValue that reads all the data from a single HDF5 file is available. For more information regarding the structure of the file see The HDF5 file format.

The modified boundary condition is called timeVaryingMappedHDF5FixedValue and can be downloaded at https://bitbucket.org/lesituu/timevaryingmappedhdf5fixedvalue

If this boundary condition is used the entry in the U file should look as follows.

inlet
{
type            timeVaryingMappedHDF5FixedValue;
setAverage      false;
perturb         0;
offset          (0 0 0);
hdf5FileName    nameofthehdf5file.hdf5;
hdf5PointsDatasetName    points;
hdf5SampleTimesDatasetName    time;
hdf5FieldValuesDatasetName    velocity;
}