I have a 3D FSI simulation which is an elastic cup that deforms by contraction to drive a flow. I have been able to get the 2D version to work, but the 3D version does not seem to function. I am using the dynamic mesh with smoothing, layering and remeshing, but I do not see any of that happening. I have tried:
- Springs with Spring Constant 0 and Convergence Tolerance 0.001 for All Elements
- Diffusion with boundary-distance and Diffusion Parameter 0.1
- Linearly Elastic Solid with Poisson's ratio 0.25 and also 0.35
- Height Based with Split Factor 0.4 and Collapse Factor 0.1
- Local Cell, Local Face, Region Face with Minimum Length Scale set to 0, Max to 0.002
- Also I tried CutCell Zone on and off.
In the Dynamic Mesh I have the boundary as System Coupling with Cell Height 0.001. I also have the fluid_body as Deforming with Remeshing and Smoothing enabled.
My mesh has a Body Size Function on the elements so that they are tetrahedrons of size 0.001.
The problem is every single combination of these produces results like those shown in the gif - there is no change no matter which of the various settings I have tried. All of the combinations produce results that look just like these. I have highlighted several nodes for consideration. Notice that there is no remeshing, no internal movement, nothing happens to the internal nodes at all. Shown is the symmetry plane as assigned in Fluent, and the solution up to the point of error. I need to continue the deformation much further past this point, but the Negative Cell Volume error keeps stopping the solution.
1. I am getting a negative cell volume error. What should I look to change in order to get some kind of response from the Mesh Methods settings? Right now none of them seem to have ANY effect whatsoever.
2. What is the difference between interior-fluid_body (interior, id=1) and fluid_body (fluid, id =4) in my model tree. Should I be setting the deforming to one or the other or both?? When I try to use the Graphics>Mesh I cannot plot the mesh for fluid_body or fsi_fluent. Why?