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-   -   the continuity residual is not converging (https://www.cfd-online.com/Forums/fluent/185067-continuity-residual-not-converging.html)

Cakov March 17, 2017 23:23

the continuity residual is not converging
 
file:///C:/05_AS002BEME5/mecca/mecca02_files/dp0/FLU/Fluent/SYS.2-5-00248.jpg

i am simulating a car park with jet fans. both inlet and outlet of the fans are labeled with fans(boundary condition). the pressure jump at the outlet is 700Pa.
a steady state, standard k-e turbulence, pressure-velocity is coupled.

how to reduce the continuity residuals? pls help me!:confused:

CFD-fellow March 18, 2017 05:25

Hi
If your setup is correct then try increasing your mesh density in high gradient regions.

GregCFD March 19, 2017 04:02

What's your mesh quality like?, I've generally found that continuity is particularly sensitive to the quality of the mesh and won't converge when the other quantities will.

p.s.

With images I find it's best to upload then to a storage website, like Imgur, first and then link them here. I don't think you can directly upload to to here (anymore?).

Cakov March 19, 2017 05:53

Quote:

Originally Posted by CFD-fellow (Post 641240)
Hi
If your setup is correct then try increasing your mesh density in high gradient regions.

i am not very sure about the setup. most of it i just leave it at default.
But i did increase the number of mesh but the continuity residuals is still at 10^-2

Cakov March 19, 2017 06:02

Quote:

Originally Posted by GregCFD (Post 641316)
What's your mesh quality like?, I've generally found that continuity is particularly sensitive to the quality of the mesh and won't converge when the other quantities will.

p.s.

With images I find it's best to upload then to a storage website, like Imgur, first and then link them here. I don't think you can directly upload to to here (anymore?).

My mesh size function is proximity.
Relevance center is fine.
Smoothing is high
Transition is Fast
Span angle center is fine

The rest is set as default.

BlackHeartInertia July 20, 2017 16:15

I have the same problem. I decided to accept that value and and use more convergence criteria.

Maybe someone here that knows more than us can say if this is ok or not

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