I am trying to simulate a cantilever cylinder subjected to a fluid flow (3D) using 2-way FSI. The expected displacement is less than 2 times the diameter of the cylinder (in my case, 10 mm) so I decided to simulate this displacement on the tip of the cylinder in still water to check the mesh deformation and this is where I'm trapped.
I separated the fluid in two zones: one around the cylinder to capture the boundary layer, and the other with the rest of the fluid. Both have cylindrical shapes. In dynamical mesh, I selected the smoothing (spring on all cells) and layering method. The spring method allowed me to select "Deform adjacent boundary layer with zone", which maintains the shape of the boundary layer zone.
\i have two types of problems depending on if I select "share" or "group" between fluid zones in the "shared topology" section in Spaceclaim:
- The "boundary layer fluid" zone penetrates the "rest of the fluid" zone as the cylinder moves. It's like both zones were detached. I find this weird since its the same material (water) and fluent recognises it as an interface zone.
- The "rest of the fluid" zone moves along with the movement of the cylinder+"boundary layer" zone. It doesn't absorb it in the interface region between zones. I can see that the cells along the outer wall of my model absorb the motion, which is problematic. In addition, it seems that the layering method doesn't work since I don't see any splitting of collapsing cells throughout the movement.
Sorry for the long post. In summary, my goal is to create a mesh that is able to absorb the cylinder's movements and, to preserve a high quality boundary layer zone.
I attached an image to clarify my problem. This is just a test, that's why the mesh is not decent.