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-   -   System Coupling Restart Problem (https://www.cfd-online.com/Forums/fluent/132034-system-coupling-restart-problem.html)

SonyCFD March 24, 2014 18:48

System Coupling Restart Problem
 
Hello All !
I am using System Coupling in Ansys 14.5 for a 2Way- FSI transient Analysis.
I am facing an issue in the restart of the simulations.

Every time I restart, after finishing the first iteration of Ansys structural and fluent the simulation crashes display an error as below -
"pure virtual method called
Terminating/opt/ansys_inc/v145/aisol/.workbench: line 141: 9637 Aborted"

Has anyone come across this.

Thanks !!

stumpy March 26, 2014 08:55

What OS are you running on and are Fluent and Ansys structural running in serial, shared parallel or distributed parallel?

SonyCFD March 26, 2014 19:41

Hi Stumpy !
I am using Linux (RHEL)

I have tried to restart on two separate Linux machines (one with RHEL 5.7 other with RHEL 6.5) , but in both cases the restart simulation fails after the first coupling iteration and gives the same error (Pure Virtual method called...)

Fluent is running parallel across 4nodes(8cpus) each. I am not sure how fluent uses memory (shared or distributed)
Ansys is running on 1 node (8cpus) in parallel using the 8 cpus using the memory of the same node.

Thanks

stumpy March 27, 2014 08:31

Is the restart consistent with the way the first part of the run was completed? I think Ansys (MAPDL) would be very sensitive to any machine or OS change on a restart. If Ansys was run using the distributed option (even though everything's running on the same machine) then you cannot change the number of CPU's on a restart either. Fluent itself should be robust to changes in OS or number of partitions on a restart, but when combined with System Coupling it may not be. If the number of partitions change then it's possible the node numbering on the FSI interface changes, which would mess up System Coupling. Version 15 is more robust for restarts, but you would not be able to restart a 14.5 case in 15.0; you'd have to run from scratch.


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