Hunter Wang
Ansys Employee

I was able to replicate the issue you reported. Fixed by adding -scheduler_tight_coupling or -scheduler_custom_script.

Change your:

fluent 3ddp -g -i journal_file -t$NSLOTS

to:

fluent 3ddp -g -i journal_file -t$NSLOTS -scheduler_tight_coupling

or:

fluent 3ddp -g -i journal_file -t$NSLOTS -scheduler_custom_script

It should not relate to OS version of UGE version, but Fluent version. The 2 flags work for 2021 R2 and new releases.