I´m developing a tool to generate an openFoam wind tunnel case. I already have the blade geometry constructed, but I'm really new to CFD and parametric meshing. I found some articles where they mention the existence of O,C,H and I topologies to mesh the airfoil and also some software (bladedesigner) that use a topology named O10H, but none of these has a reference about how to implement the geometry of these topologies and if there are others. They also do not specify what the best use cases for each one.
Can someone help me to get started making an efficient mesh for my tool?
in the attached file show an example of the different s mesh topologies that I found, and also my example blade
Dear Eduardo,
such mesh topology can be achieved with blockMesh, the std utility of OpenFOAM just by splitting correctly the domain and to add inflation/layering.
Otherwise you can create a parametric mesh by using Salome. You can handle the meshing with python scripts, export the mesh into the UNV format and than convert the mesh into the OF format with the ideasToFoam utility.
Franco
Hi Franco, thanks for your reply.
That's what I want to do, create the blockMeshDict for OpenFOAM. But I don't know how to properly split the domain, if there are recommendations for that or simply split it and testing, using C, O or H shape
Eduardo
Dear Eduardo,
Working with mesh generation is hard stuff. Sorry for that, but it is plain truth. Most probably your best option will be an unstructured mesh. Because you're new to CFD, I would suggest some basic insight in mesh generation, what might help you with the decisions and the work to come. Have a look at Distmesh, a simple mesh generator developed for MatLab, and that will permit you to generate an airfoil mesh without much trouble. Don't try to get too much involved with the code, just try to run the airfoil case, which comes ready to run. You can download the code and some tutorials from http://math.mit.edu/~persson/mesh.
I would recomend ICEM CFD. It is easy to create a o-grid around the turbine blade and export this mesh to Openfoam.
Go for Turbogrid it is particularly design for creating automatic hexa mesh around blades profile. Besides, you can also follow ICEM for meshing but you wont able to create automatic blade passage in ICEM.
generation of structured meshes for 3-D complex geometries is a real pain (which i suffer lately for a turbine blade). In your case, because you use an unstructured solver, you can follow a hybrid mesh approach. just wrap a thin O-mesh (i mean hex mesh) around the blade encompassing about the boundary layer. Then construct unstructured tetra for the rest of the domain. This approach would be quite easy and efficient in my experience.
For the generation of high quality structured meshes for wind turbines, you can use Numeca's Autogrid software.
http://www.crses.sun.ac.za/files/research/completed-research/wind/wt_pierce.pdf
Though not the topology you're looking for, I have put together a case with a 3-D blade in a towing tank. The mesh is created with OpenFOAM's blockMesh and snappyHexMesh tools, so there are no external dependencies. The blade geometry is an STL file located in the `constant/triSurface` directory. The case repository is attached.
https://github.com/petebachant/NACA0020-3D-OpenFOAM
You can try to use Salome that is a little bit more user friendly than snappyHexMesh.
Franco
Hi. I finally made my first attempts with OpenFOAM blockMeshDict which are in https://github.com/efirvida/3D-OpenFoam-Wind-Blade. I finally decided to use a similar topology to the OH that is better adapted to the curvature of the domain that I am using
Now I have a new question, which is perhaps better to put in another thread. And the question is.
Is there any way to make a circular array pattern with the domain to generate a cylindrical computational domain?
thank you all for the help
Dear sir (Eduardo Fírvida)
The link you have given is broken. Can you resend the files
https://github.com/efirvida/3D-OpenFoam-Wind-Blade
Maybe it is too late, but it could help someone else. Smart people made this usefull tool for OpenFOAM :
http://hvirvel.dk/airfoilmesher/