How to set up rough wall conditions

weigsi · February 27, 2011, 14:26

Hi there,
i have created a tube D=0,2m, and use the k-Omega SST Model with All y+ treatment, y+ is around 25.
i set up the wall conditions in regions as rough, and there is a difference to smooth wall in the pressure drop (over to section planes i have created) but i cant manipulate the Roughness function as i want.
i mean the pressure drop with roughness height 0.0001 is the same as 0.01... 1.... 10... 100.
What does this roughness height stand for? and is there any mistake if have done in meshing/physic model or something?
thx for your help
best wishes weigsi

Vinicius · February 28, 2011, 10:09

It´s not just the roughness value, it depends of the first layer size.

See in the user guide, there is an explanation of how the wall treatment curve is adjusted depending on the roughness value....

regards,

Vinicius

February 27, 2011, 14:26	How to set up rough wall conditions	#1
weigsi New Member hhuh huhu Join Date: Jan 2011 Posts: 9 Rep Power: 15	Hi there, i have created a tube D=0,2m, and use the k-Omega SST Model with All y+ treatment, y+ is around 25. i set up the wall conditions in regions as rough, and there is a difference to smooth wall in the pressure drop (over to section planes i have created) but i cant manipulate the Roughness function as i want. i mean the pressure drop with roughness height 0.0001 is the same as 0.01... 1.... 10... 100. What does this roughness height stand for? and is there any mistake if have done in meshing/physic model or something? thx for your help best wishes weigsi

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February 28, 2011, 10:09		#2
Vinicius Member Vinicius Girardi Join Date: Mar 2009 Location: Sao Paulo, Brazil Posts: 80 Rep Power: 17	It´s not just the roughness value, it depends of the first layer size. See in the user guide, there is an explanation of how the wall treatment curve is adjusted depending on the roughness value.... regards, Vinicius