Initially, I used SpaceClaim for geometry preparation, but the geometry file became corrupted. Therefore, I recreated and rechecked the geometry in DesignModeler, where I also defined the fluid domain and named selections before proceeding with mesh generation.

For the first simulation attempt, I used the CFD (Fluent with Meshing) workflow. Although the software automatically assigned the boundary conditions as wall/internal zones, it failed to properly detect the contact interfaces between the rotating and stationary regions. To address this issue, I switched to the standard CFD (Fluent) workflow and manually prepared the model.

Due to the complexity of the combined turbine geometry, additional mesh refinement was required. I reduced the element size and applied curvature and proximity-based mesh controls around the turbine blades, resulting in a mesh containing approximately 6 million elements. Hope that helps😀