Time-Step and Simulation time not increasing and fixed at "0"

gaddora165 · May 2, 2019, 00:23

I am facing a quite vague issue. that iteration is working fine but the time-step and simulation time not increasing and fixed at "0" ...

can anyone advise on how i can rectify this please ?
any suggestion ?

please refer to the screenshot attached.

fluid23 · May 2, 2019, 13:42

If its a transient solution and at 35 iterations, have you even completed the first time step yet? What is your inner iteration stopping criteria? What does your residual plot look like?

gaddora165 · May 3, 2019, 10:03

its a turbulent flow and implicit unsteady solution.
i'm not able to even go for the 1st time step and as you can see time step and simulation time is fixed at "0" ...

anyone can help please ?

LuckyTran · May 3, 2019, 14:10

Follow the directions! A time-step involves both solving the solution at that time and the many iterations (35 in your case) needed to solve that time. You have done the 35 iterations, now you need to move to the next time-step.

Normally this is a no brainer but maybe you can describe what your settings are that causes it to break on iteration 33 and why it doesn't automatically go to the next time-step.

What is the stop criterion? Did you tell it to stop after 0 time-steps or something?

gaddora165 · May 3, 2019, 23:44

here are my stopping criteria setting (refer to attached picture)
I have tried to use different options and also many trails but yet the time step or simulation time is increasing.

fluid23 · May 6, 2019, 10:17

You don't have your inner iterations enabled so it will never break out of the first time step. Each time step in the implicit solution is like its own steady solution. You have to converge your residuals and figures of merit at each one before proceeding to the next time step. If you would post a plot of your residuals and any reports/monitors you are tracking, this would be an easier conversation.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
courant number in vof	reza_gharib1369	FLUENT	49	February 26, 2020 16:55
2 fixed inlet velocities lead to steady time step decrease in interFoam	rheise	OpenFOAM Running, Solving & CFD	7	July 3, 2017 06:24
time step directories naming issue	Andrea_85	OpenFOAM	3	April 3, 2014 08:38
Nozzle rhoSimpleFoam transonic --> time step increase	erichu	OpenFOAM Running, Solving & CFD	2	May 3, 2013 12:54
How to find a good time scale strategy?	StefanG	CFX	19	June 8, 2012 08:41

May 2, 2019, 13:42		#2
fluid23 Senior Member Matt Join Date: Aug 2014 Posts: 947 Rep Power: 17	If its a transient solution and at 35 iterations, have you even completed the first time step yet? What is your inner iteration stopping criteria? What does your residual plot look like?

May 3, 2019, 10:03		#3
gaddora165 New Member Mohamed Join Date: Jan 2019 Posts: 21 Rep Power: 7	its a turbulent flow and implicit unsteady solution. i'm not able to even go for the 1st time step and as you can see time step and simulation time is fixed at "0" ... anyone can help please ?

May 3, 2019, 14:10		#4
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,675 Rep Power: 66	Follow the directions! A time-step involves both solving the solution at that time and the many iterations (35 in your case) needed to solve that time. You have done the 35 iterations, now you need to move to the next time-step. Normally this is a no brainer but maybe you can describe what your settings are that causes it to break on iteration 33 and why it doesn't automatically go to the next time-step. What is the stop criterion? Did you tell it to stop after 0 time-steps or something?

May 6, 2019, 10:17		#6
fluid23 Senior Member Matt Join Date: Aug 2014 Posts: 947 Rep Power: 17	You don't have your inner iterations enabled so it will never break out of the first time step. Each time step in the implicit solution is like its own steady solution. You have to converge your residuals and figures of merit at each one before proceeding to the next time step. If you would post a plot of your residuals and any reports/monitors you are tracking, this would be an easier conversation.