CFX Convergence
 

In CFX is there any way to control convergence by body force ie stop calculation when force is within x Newtons?

It is better to stop solution when body force change become very small from iteration to iteration.
Here is article where explained how to setup solution interruption. An article is on Russian language but you can translate page via google or simply look on pictures.
https://cae-club.ru/publications/kog...reshenie-v-cfx