Fluids

Fluids

Input Journal for a transient CFD-Simulation in Batch mode

    • Monta
      Subscriber

      I am trying to run a simulation (transient flow) on a HPC-System. Fluent is supposed to read a case and data then run a calculation, for which I define time step, number of time steps & number of iter/time-step. The input Journal looks like:

      -------------------------------------

      rc SYS-3.1-1-00923.cas.gz

      rd SYS-3.1-1-00923.dat.gz

      solve/time-step 0.01

      solve/dual-time-iterate 1000 100

      wc Ergebnis.cas.gz

      wd Ergebnis.dat.gz

      exit

      yes

      --------------------------------------

      In the output file the only problem is with the 2 command lines:

      solve/time-step 0.01

      solve/dual-time-iterate 1000 100

      since I get for both the error:

      Error: = (equal): invalid argument [1]: wrong type [not a number]

      Error Object: #f

      Reading & writing case & data files are totally fine! There is no problem.

      I searched in Internet & in many documentations are the two command lines used. So here is my question are the command lines to run transient simulation correct?


      Thanks for the help!

      Monta.

    • DrAmine
      Ansys Employee
      If you open Fluent interactive mode you might test the commands and check if they are working
    • DrAmine
      Ansys Employee
    • DrAmine
      Ansys Employee
      Always record journal files first by trying different commands interactively
    • Monta
      Subscriber
      So trying the command line solve/dual-time-iterate interactively worked. That's why I am asking why did this one command line cause a problem in batch mode while starting the simulation on HPC-System.
    • Monta
      Subscriber
      An update to what I tried to figure out the problem. I opened the case & then the data file in Fluent interactively on the cluster. I tried to run the simulation through the GUI and through TUI to see if the problem only occrus when Fluent reads the journal in batch mode. I get the same problem ( see the Foto)

      Maybe there is someone here who already had experience with such erros and can guess what can cause it.
      Remark: The case and data files were generated by Fluent 2021R2 & here I am trying to continue the simulation in HPC system with Fluent 2020R2 ( only available).

      thanks!
    • DrAmine
      Ansys Employee
      So step back: When are you starting getting that error message? After reading the case?
      Please use the full command as follows /solve/dual-time-iterate 1 100
    • Monta
      Subscriber
      Problem solved! It is apparently so: I prepared my case locally with fluent 2021R2 and generated initial data for the hpc simulation. On the HPC-System is only fluent 2020R2 so far available. So running the simulation on a earlier version causes this error! This leads me now to the next question:
      why I cannot carry on a simulation with 2020R2, which already been created and run in 2021R2?
      Is there a way to adapt the simulation to the earlier version or solve this issue?

    • DrAmine
      Ansys Employee
      1/You should be able to do that. But you cannot run a case built up in newer version in an older version: that will generally result in issues ( that is what you wrote you prepare in 2021r2 and want to run in 2020r2).
      2/I always recommend to create a journal which reads the mesh, setup the case and then run it. This should be release agnostic as much as possible: it will also contain a line telling Fluent which TUI version to be used.
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