# Set properties of cells inside domain

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September 23, 2022, 14:50
Set properties of cells inside domain
#1
New Member

Rodrigo Villarreal
Join Date: Nov 2016
Posts: 20
Rep Power: 8
I need to assign the thermal conductivity of the "layer" of cells next to the boundary to the adjacent "layer" of cells inside the domain.
In the attached image, it will be something like assign the thermal conductivity of the orange line to the green line.
Does anyone know how to do it or if is it possible?
Attached Images
 figurin.png (6.9 KB, 9 views)

 September 25, 2022, 17:06 #2 Senior Member   Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,636 Rep Power: 25 If it are different solids, then you should create a volume with only the orange elements, assign it to a new material with a different conductivity.....If you have a liquid and are trying to modify the conductivity close to the wall, then there must be a specific reason. If so, then what are you trying to do exactly?

 September 25, 2022, 19:30 #3 New Member   Rodrigo Villarreal Join Date: Nov 2016 Posts: 20 Rep Power: 8 I'm trying to decrease an enormous gradient near the wall by making thermal conductivity artificially high. The huge gradient of temperature is created by resistive heating due to an electrical current that passes through the fluid. I've tried a constant value, but it doesn't work properly.

 September 28, 2022, 16:19 #4 Senior Member   Erik Join Date: Feb 2011 Location: Earth (Land portion) Posts: 1,115 Rep Power: 21 It does not sound like what you are trying to do is realistic. The artificially high conductivity of the fluid is not realistic, and it any results obtained using it would be meaningless, so i don't understand the reasoning for trying to do this. But If you really wanted to, you could probably make the conductivity a function of y (or another location based definition)

 September 28, 2022, 17:27 #5 New Member   Rodrigo Villarreal Join Date: Nov 2016 Posts: 20 Rep Power: 8 Thanks for your reply. Yes, it's not realistic, but I'm trying to see if it works. I'll try the location based approach.

 October 8, 2022, 05:32 #6 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,231 Rep Power: 135 This sounds like a classic XY problem to me (https://en.wikipedia.org/wiki/XY_problem) Why do you think this gradient is unrealistically high? Is it is problem anyway? If you are just adding heat to a liquid it might not matter if the gradients are huge. Should there be other physics at play (eg boiling?). Do you need a finer mesh to resolve it properly? Or maybe a turbulence model? __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

 Tags cel fortran cfx, cfx, cfx + fortran