Ansys Employee

If you're running coupled Fluent and Rocky you'll benefit from 2023R1 as the coupling was new in 2021R2: it's since been improved. You also want to check cpu load when running Fluent, you've not mentioned cell count, or what the operating system is. 

No idea about the mpi settings - I rely on our system being set up. I'll get one of the install group to comment.