Now that all mesh regions are finished, they can be used both separately (for multi-region case) or merged into a single mesh (for single-region case). In this tutorial we will use the latter choice. As a first step we copy some of the meshes to a new directory. For example:

# cp -R mesh-inflow mesh-whole
Now change to the new directory and merge the remaining two meshes with this one:

# cd mesh-whole
# mergeMeshes . ../mesh-wheel
# mergeMeshes . ../mesh-volute
The first dot as an argument of mergeMeshes stands for the current directory (master case) and the second argument stands for the case to merge with the master case. The merging will present zones, including the rotating cell zone of the wheel.

The last step of the mesh genesis is renaming of the patches, dropping of empty patches and merging of some other patches. This is managed by the utility createPatch, which can create new patches from old patches or from face sets. Here we use only the former functionality. The settings for createPatch is in the file system/createPatchDict. Its contents are:

pointSync false;

patches
(
    {
        name            wheel_inlet_1_ami;
        patchInfo       { type cyclicAMI; neighbourPatch wheel_inlet_2_ami; }
        constructFrom   patches;
        patches         ( wheel_inlet_1 );
    }
    {
        name            wheel_inlet_2_ami;
        patchInfo       { type cyclicAMI; neighbourPatch wheel_inlet_1_ami; }
        constructFrom   patches;
        patches         ( wheel_inlet_2 );
    }
    {
        name            wheel_engine_wall;
        patchInfo       { type wall; }
        constructFrom   patches;
        patches         ( wheel_pivot_wall wheel_pad_wall );
    }
    {
        name            volute_engine_wall;
        patchInfo       { type wall; }
        constructFrom   patches;
        patches         ( volute_pivot_wall volute_pad_wall );
    }
    {
        name            wheel_outlet_1_ami;
        patchInfo       { type cyclicAMI; neighbourPatch wheel_outlet_2_ami; }
        constructFrom   patches;
        patches         ( wheel_outlet_1 );
    }
    {
        name            wheel_outlet_2_ami;
        patchInfo       { type cyclicAMI; neighbourPatch wheel_outlet_1_ami; }
        constructFrom   patches;
        patches         ( wheel_outlet_2 );
    }
);

Every block separated by curly braces will create a new patch. The blocks contain the name, patch information and source information for the new patches. For example the last block will create a new patch wheel_outlet_2_ami of type cyclicAMI from original patch wheel_outlet_2_patch0. If there are more than one source patches, the new patch will be a merge of them. The utility is executed by

# createPatch