I have been working on a code for simulating a turbulent jet. For the base of my code, I have used the gridRefinement3D example, which uses the “OctreeGridGenerator< T >” Class Template. So far, things have worked fine. However, I have two main problems:
I want to obtain a symmetric simulation. However, due to the refinement process, I get a slightly non symmetric grid, as it can be seen in the figure below (slice of a plane normal to the inlet flow).
In this case, in the congif.xml, I chose nBlocks= 6. It can be perceived that the block size is always 6, except for those blocks at the left of the image, close to a refinement level transition, where the block size is 5.
I am not pretty sure about what causes this difference in the block size, but i think that it may have something to do with the way in which the octree is built with the OctreeGridGenerator class.
In the “Octree in finest units” .stl file, I can see that the level boundaries are treated in a different way, as the bottom and right boundaries of each level are perfectly aligned with the rest of the levels, but the upper and left boundaries are not aligned in the same way, causing a slightly unsymmetrical refinement.
On the other hand, when trying to extract the .vtk data of the simulation, I have realized that there is an actual physical gap in between each level. I would provide self explanatory photos, but they won’t let me, as new users can only link one photo.
I don’t really know if there is a way I can fix the symmetry problem, or the physical gaps problem (maybe with some type of overlap), but I will appreciate any type of help you can provide. Of course, if you need more information about the code or the setup, I will be happy to provide it.
Thank you very much for your attention,
Ignacio Garcia Lobo