Ansys Employee

You can't change the number of processes once the solver is running. You can stop iterating, save, close and then when reopening Fluent change the core count. Fluent will automatically repartition to the new core count. 

Note, the GPGPU offload isn't the full gpu solver so read the documentation before switching it on. It has some benefits for certain models but isn't the (new) full gpu solver that's in 2023Rx.