Residuals show oscillating behaviour !

anon_l · October 30, 2016, 07:09

Hello all,
I am trying to run a simulation with supercritical H2O through a simple tube geometry with thickness (conjugate heat transfer).
on running the simulation , my residuals seem to oscillate . Can someone please explain me how I should fix this ?
I am including a pictue of my residuals in this post.

Thanks

lcarasik · October 30, 2016, 15:38

Your residuals actually look ok for the most part. An appropriate approach to tracking residuals is to look for several orders of magnitude reduction (as you see in your plot) and for the residuals to "steady out" after a large enough reduction. Eventuality all residual plots will start to show oscillations which is fine, it's just a matter of when and where they start to oscillate.

Further, are you tracking the change in mass flow or pressure drop? Or any other quantity of interest per iteratons?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
rhoSimpleFoam - strange behaviour of the residuals	Werne	OpenFOAM Running, Solving & CFD	2	December 16, 2014 05:27
Reason for oscillating residuals	fayaazhussain	Main CFD Forum	3	August 21, 2014 11:31
Oscillating residuals and no convergence!	Sherlock_1812	OpenFOAM Running, Solving & CFD	7	August 20, 2014 10:39
Strange residuals behaviour	xxxx	Main CFD Forum	1	July 13, 2013 15:40
Oscillating Residuals in Finer Mesh Case	Jake	FLUENT	3	June 16, 2005 10:34

October 30, 2016, 15:38		#2
lcarasik Senior Member Lane Carasik Join Date: Aug 2014 Posts: 692 Rep Power: 15	Your residuals actually look ok for the most part. An appropriate approach to tracking residuals is to look for several orders of magnitude reduction (as you see in your plot) and for the residuals to "steady out" after a large enough reduction. Eventuality all residual plots will start to show oscillations which is fine, it's just a matter of when and where they start to oscillate. Further, are you tracking the change in mass flow or pressure drop? Or any other quantity of interest per iteratons?