System Coupling (FSI) failure when trying to start from a previous solution in Fluent

    • Ivan_stream

      Hi. I am performing a two-way FSI analysis in 2021R2 with Transient Structural and Fluent as coupling participants. The problem has been setup in Workbench. Then, the System Coupling setup has been exported to be solved in a cluster. Previously, the Fluent transient case has been solved separately to obtain a more or less stable solution after 100 s, in order to provide initial conditions for the coupled analysis, since it involves the MHD module and requires a fine mesh and very small time steps. This approach allows avoiding excessively long calculation times in comparison with starting from a standard or hybrid initialization.

      Once launched the calculation in the cluster, a python script loads a journal file as Initial Input for Fluent. The *.jou file includes, among others, a command line to read the case file and other to read the data file:



      The Coupling Solution fails during the first iteration: Error when making a remote call to participant Solution 1 (that is, Fluent).

      When consulting the Fluent output, it seems that both the case and the dat have been correctly loaded. However, after executing (sc-solve), this error appears:

      Fluent Sending SCAnalysis:FatalErrorSC Fluent encountered fatal error

      On the contrary, when the read-data command is substituted by initialization command lines, like:

      (if (hyb-init?)

      (ti-menu-load-string "/solve/initialize/hyb-initialization")

      (ti-menu-load-string "/solve/initialize/initialize-flow"))

      then the analysis works well to the end of the calculation. I have tried other alternatives: using the read-case-data command, importing Ensight Gold data, using profiles, etc., but none has worked. So my question is wether it is possible to start the Fluent solution in a FSI System Coupling analysis from a previous calculation, when the problem is being solved in a cluster (I know it works when it is solved in Worbench)?

      Thank you very much for your help.


    • Stephen Orlando
      Ansys Employee

      Can you confirm that you can manually load the .cas and .dat and run the case?
      Try /file/read-case-data.
      Please copy and paste the entire .jou into your reply.
      Do you have access to 2022R1? With this version we added an option to specify the Fluent .dat in the SyC GUI.
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