PRefCell not constant

C-L · June 6, 2017, 13:42

Hi all,

I am simulating a fully developed channel flow using RANS and cyclic boundary conditions. In order to do so I need to specify a reference pressure at a certain location. I have chosen a cell on one of the wall boundaries to have a reference pressure of 0 BUT after checking the converged solution the pressure at this cell is 0.029. I assumed the reference cell would maintain the reference pressure throughout the whole simulation - is this not the case?

Thanks in advance.

khedar · June 11, 2017, 15:47

Just wondering, is it okay to put reference cell on the wall? Since normally we apply zeroGradient condition on the wall.

C-L · June 11, 2017, 15:58

I assumed that it wouldn't matter but you might be right. However, I'm not sure where else to put the reference point in a periodic channel. I need to be able to calculate forces on the wall so wouldn't they be dependent on the pressure field? And wouldn't changing the reference point subsequently change the force calculations?

Thanks for the reply.

June 6, 2017, 13:42	PRefCell not constant	#1
C-L Member Charlie Lloyd Join Date: Feb 2016 Posts: 57 Rep Power: 10	Hi all, I am simulating a fully developed channel flow using RANS and cyclic boundary conditions. In order to do so I need to specify a reference pressure at a certain location. I have chosen a cell on one of the wall boundaries to have a reference pressure of 0 BUT after checking the converged solution the pressure at this cell is 0.029. I assumed the reference cell would maintain the reference pressure throughout the whole simulation - is this not the case? Thanks in advance.

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June 11, 2017, 15:47		#2
khedar Senior Member khedar Join Date: Oct 2016 Posts: 111 Rep Power: 10	Just wondering, is it okay to put reference cell on the wall? Since normally we apply zeroGradient condition on the wall.

June 11, 2017, 15:58		#3
C-L Member Charlie Lloyd Join Date: Feb 2016 Posts: 57 Rep Power: 10	I assumed that it wouldn't matter but you might be right. However, I'm not sure where else to put the reference point in a periodic channel. I need to be able to calculate forces on the wall so wouldn't they be dependent on the pressure field? And wouldn't changing the reference point subsequently change the force calculations? Thanks for the reply.