Propeller Design with OpenFOAM
FRIENDSHIP SYSTEMS prepared an example for linking CAESES® to OpenFOAM for a workshop that was held in October 2014. The following summary is also available as tutorial, see the section “More Information” below.
The blade is generated by using the “Generic Blade” type of CAESES® . With this, one can define custom profile descriptions, as well as radial distributions for each profile parameter. The whole shape is finally controlled by a set of design variables. These variables are then modified automatically by means of design engines (variation and optimization algorithms) in a next step.
In order to plug-in OpenFOAM into CAESES®, a software connector is used. In a single window of CAESES®, the user can simply drag & drop the geometry into the export section of the connector, for exporting the blade in a multibody STL format. With this specific STL flavour, colors help to group together different parts and boundary definitions.
All required input files (for this example from tutorials/incompressible/pimpleDyMFoam/propeller) are directly loaded as a copy into CAESES®. Within an embedded editor of CAESES®, these files are then manipulated in a next step. For the following scripts/files, user-defined parameters are introduced:
- Allrun script
Results files of OpenFOAM (forces.dat, cases.foam) are also specified in the software connector. Values from the ASCII file are automatically extracted and loaded into CAESES®, to make use of them for automated design studies and shape optimization. Finally, interactive 3D postprocessing and different plots are available in CAESES® by using the case.foam file.
Running OpenFOAM within CAESES® is simply done by means of a “computation” object that triggers the Allrun script with a single click: Then, a geometry variant gets exported, meshing is triggered, CFD is started and results are pushed back into CAESES® – everything works fully automated.
This work is described in detail in a PDF tutorial that comes with CAESES®. There is also a video (CAESES as a GUI for OpenFOAM) in our video section. And, here is a nice blog post (blade analysis for propellers) which shows how to quickly generate a fully-parametric blade model from a set of given NURBS surfaces (for blade designers).
If you have further questions about coupling CAESES® and OpenFOAM, please drop us a line, or take a look into the CAESES® forum where plenty of posts deal with this topic (just enter e.g. “OpenFOAM” into the search field).
See also the marine section for related content about propeller design.