> FOAM FATAL ERROR: Maximum number of iterations exceeded
hi everybody,
I'm solving free convection in 3D in OpenFOAM. my model is a cubic that its bottom temperature is at 400K and the upper plane is at 300K. the sides are isolated. I'm using buoyantPimpleFoam and when I ran it the below error appeared: Code:
Thank you 
The crash occurs because there is no convergence when solving for the temperature from the enthalpy using the hConst species thermo model. Have a look at the following thread for some insight into what is happening:
Declaration of function TH() As for how to fix it, have a look at your enthalpy values and see what they are doing. It could be failing for any number of reasons: Newton's Method  Failure Analysis How many iterations have you run when it crahes? Do you notice anything odd about the temperature? Make your write interval smaller to try and see where the problems occur. 
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Thank you for your reply. this is the full results: Code:
/**\ 
You've got a lot of problems with your case setup; rho, k and epsilon are all blowing up! My guess is that paying more attention to your boundary and initial conditions will solve the issues. Have a look at the tutorial cases and see if your boundary conditions are consistent for walls and open boundaries.

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Thanks Marco, I'm trying to solve natural convection in a closed box. in first post I explain it. I check the boundary, they are alright. I'm so confused! I guess this errors are originated from my meshes. I should check it. 
hi
My bottom temperature is 3000K. when I reduce it to 400K there is no error!!! why?!? anybody knows? 
What do you mean bottom temperature? Bottom of the room, bottom range of interpolation?

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but I think they aren't true. the convection occurs weakly, but temperature is pretty high!!!! 
Sounds like its a matter of tweaking the model, maybe selecting a different species thermophysical models. I haven't done much with free convection, so you'll have to ask someone with more experience.

Maybe you can try a lower deltaT in you controlDict file.
Regards 
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I tested it, again the convection was very weak. I solve this geometry with Fluent and it solved it correctly. but I don't understand why the temperature distribution is wrong?!?!?!? actually in my model the convection doesn't occur. the bottom plane remains at T=1000K and the rest remains T=300. do you know what is wrong? 
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I don't have too much experience in free convection. Maybe a person with more knowledge can help you. But i suggest you to have a look at this tutorial by Abolfazl Shiri: http://www.tfd.chalmers.se/~hani/kur...i/NC_Shiri.pdf Regards Mojtaba 
hi everybody,
again this error appears: Code:
> FOAM FATAL ERROR: please Help me:( 
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thank you Mojtaba 
I could solve it by defining zeroGradient boundary condition for p and p_rgh

Hi,
I m having the same Problem with my case. I m trying to simulate a constraction in free convection. After the first Time step i get: maximum number of iterations has been exceeded. exact the sameone that Mostafa got. can i post my case so you expert :) can take a look in it? because I tried everything and nothing seems to be working :confused:. I change the BC, the solver for AIR, the Delta, checkt the initial condition, working with other Relaxations Factores and checkMesh can find no problem with my Mesh. My porbleme apears when OP calculate h for my Air region. the T value seems to go higher then it should be. Please Please someone help. to Mostafa: dose your case work now? can you please post it ? Regards 
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Maybe you can use some bounded Div schemes in your fvscheme file. Try to play with different combinations of schemes. Try to use more bounded ones, instead of more accurate schemes. after some iterations you can change back to second order and unbounded schemes for more accuracy. best 
Hi Mojtaba,
sorry for the comend queation but i m new in OpenFoam. what do you mean with more bounded div schemes? I m using bounded Gauss upwind for all of my div schemes. Only for div(R) and div((muEff*... i m using Gauss linear. thank you Best Regards 
Hi all,
i got the same problem. I am using the buoyantSimpleRadiationFoam. The problems is always at the second time step, when solving the G file. Any suggestions to fix this problem? Thank you, Best regards 
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