how the under relaxation factors will effect convergence or results?

- May 5, 2020 at 7:40 am
  
  Weiqiang Liu
  Subscriber
  
  Hi all,
  
  I am calculating a propane catalytic combustion with single step surface and gas reaction scheme. I set the under relaxation of energy to 0.8 and monitor temperature seems keeps unchanged after a huge number of iterations.
  
  when I modified the under relaxation factor of energy to 0.9, the monitor temperature would increase 100 k higher and keep constant. when I further increase energy under relaxation factor, the monitor temperature would go higher. when I set the under relaxation factor to 1, the case diverged immediately.
  
  I wonder how under relaxation factors will effect results and convergence. How can I determine the case is fully converged?
  
  Weiqiang
- May 5, 2020 at 3:24 pm
  
  Kalyan Goparaju
  Ansys Employee
  
  Hello Weiqiang,
  
  The discussion presented in this page might help you understand the idea of under-relaxation.
  
  https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v201/en/flu_th/flu_th_sec_time_theory_seg.html%23flu_th_sec_underrelax_eqn
  
  Thanks,
  
  Kalyan
- May 7, 2020 at 9:20 am
  
  Weiqiang Liu
  Subscriber
  
  hi Kalyan,
  
  Thanks for your sharing.
  
  Best regards
  
  Weiqiang