for a Research Projekt, I am currently trying to calculate the air resistance of a rotating Torus which is encased inside another Torus with Ansys Fluent in a transient model. The following picture I hope describes what I want to achieve:
I get the model to run on a small scale in Fluent with very low accuracy.
However, the final Torus will have a Diameter of around 100 Meter and can hardly be scaled down any further in diameter and dimensions. When meshing this system with the needed accuracy and Tetragonal Cells, I end up with around 20.000.000+ Cells, which is why I try to find ways reducing the cell-count.
Currently I am trying two different methods to reduce the cell count:
1. Using Multizone/Hex-Dominant Meshing combined with sizing functions. The Problem is, that the contact region of the sliding mesh will never be meshed accurately and Ansys gives warnings.
2. Make use of the Axial Symmetry of the System and only mesh 180/90/45 degree of the Torus with applying "cyclic symmetry" to the system. With this approach, the sliding mesh will constantly "rotate out of the boundaries"
Inflations Layers are already on both of the walls.
Is there any other way to scale down a system like this, or to mesh it more efficiently?
Any help or hints will be highly appreciated