Divergence detected in AMG solver
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Hi everyone,
I'm trying to simulate a centrifugal compressor and i'm having some difficulties to get the convergence in pseudo transient method.But if i did not select the pseudo transient ,i can get the convergence. I simulate the rotation using Multiple Reference Frame (MRF). The rotor has an angular velocity of 5266 rpm, and the stator is stationary. The mesh hasnīt shown any problems when i do the mesh check. The boundaries are defined as pressureinlet and pressureoutlet and periodic. and the walls are the following: Wallstator: The walls of the stator are defined as stationary Wallrotor: Rotating walls of the rotor, defined as moving walls, relative to adjacent cell zone, with 0 velocity. i use hybrid initialization. When 130 iterations, i got the following message: # Divergence detected in AMG solver: nut > Decreasing coarsening group size! # Divergence detected in AMG solver: nut > Increasing relaxation sweeps! Error: Divergence detected in AMG solver: nut Error Object: #f I've uploaded an screenshot of the two final result Could anybody help me? Thanks. Attachment 18019 Attachment 18020 
1 Attachment(s)
so do I, the same errorAttachment 20183

Lower the Courant Number and have a try. AMG means algebraic Multigrid.

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