[Dynamo]

Hello everyone,

I have had a particle sedimentation problem for some time that I have not been able to solve.

I want to run a transient simulation of freely falling single particle in 2D as well as in 3D, in a Viscous Stagnant Fluid. To do this, I use overset mesh method and SixDOF solver to solve compute external forces and moments resulting from the interaction of the body with the fluid.

For this, I also have used a UDF in which I defined the properties of the SixDOF Solver ( mass and moments of inertia) and which was also adapted to track the components of the velocity of the CG during the fall.

I have already tested it and it is functional, however when I define very small mass units for the solver (1e-3 kg, 1e-4 kg...) divergence is detected in AMG solver with a floating point exception.

I have tried many options and I have not been able to solve it, I have changed the mesh, with quality monitoring, trying different meshing methods, turbulence models, CFL number, different time step size, using dynamic meshes instead of the Overset mesh method , different solution methods, pressure-velocity coupling, One DOF analysis but nothing has worked.

If anyone has experience on this topic, please suggest me something helpful. I can share the case files and images. I am using Ansys Fluent 19.3, 22R1 or 23R2. Thanks and excuse me for my english!

[Dynamo]

Does anyone have an idea to solve this problem?