Boundary condition updating in OpenFOAM

yzf1215 · January 28, 2014, 16:27

I have noticed that in each time step, boundary condition is updated severals times, such as, three times for Ux Uy Uz, and one time for pressure equation, other times for turbulence equation.

Here is my concern, Is it possible to reduce those repeated updating times? In my customized boundary condition code, it won't change within the same time step, which makes a huge CPU time waste to run boundary condition code for so many times within the same time step.

Thanks for helping

chriss85 · February 4, 2014, 02:58

Are you talking about updating them to match the fixedGradient/zeroGradient condition when the values of the cells change?

These can't be avoided, but if you have a fixedValue (or time dependent), it should not have to be used, because the values of the boundary are independent of the inner cells.

mxa261 · January 18, 2021, 17:07

Hi Zifei,

I have the same question. Did you find any answer?

Best,
Mehrshad

January 28, 2014, 16:27	Boundary condition updating in OpenFOAM	#1
yzf1215 Member Zifei Yin Join Date: Sep 2012 Location: Shanghai & Ames Posts: 33 Rep Power: 13	I have noticed that in each time step, boundary condition is updated severals times, such as, three times for Ux Uy Uz, and one time for pressure equation, other times for turbulence equation. Here is my concern, Is it possible to reduce those repeated updating times? In my customized boundary condition code, it won't change within the same time step, which makes a huge CPU time waste to run boundary condition code for so many times within the same time step. Thanks for helping

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February 4, 2014, 02:58		#2
chriss85 Senior Member Join Date: Oct 2013 Posts: 397 Rep Power: 18	Are you talking about updating them to match the fixedGradient/zeroGradient condition when the values of the cells change? These can't be avoided, but if you have a fixedValue (or time dependent), it should not have to be used, because the values of the boundary are independent of the inner cells.

January 18, 2021, 17:07		#3
mxa261 New Member Mehrshad Amini Join Date: Sep 2017 Posts: 10 Rep Power: 8	Hi Zifei, I have the same question. Did you find any answer? Best, Mehrshad