Hi Rob,
Sorry for getting back to this question very late, and I appreciate your response. I gave up Fluent on HPC for the running remained very slow, and I don't know about virtual or real cores on HPC. Now, I am going to use Rocky DEM on the cluster coupled with Fluent, and I think I should communicate with the IT staff again about the slow running of the Fluent. I will ask them about your question.
The Ansys version on the cluster is 21.2, The linux system is Red hat, and I have to use Openmpi for parallel run. Would you think that switching to 23.1 will probably solve the issue? Does it matter which version of openmpi to use? Is it better to use the Openmpi which is distributed within the Fluent package? And lastly, how can I get some diagnostic data while running the simulations that can help you identify any problem? I read somewhere that "show affinity" may help with that.
Thank you so much.