Wall roughness and boundary layer (y+)

gdimitris · July 16, 2017, 09:35

Hi guys,

I am introducing surface roughness in my simulation to get more realistic results, however, I observed something odd, the boundary layer in the model with wall roughness is not captured very well. The vectors are longrer and the y+ has increased from about 0.3 to 8 (max values). Is there something wrong with my simulations or do I need to make the mesh denser around the blade to get better y+ and thus capture the boundary layer?

Thank you in advance.

gdimitris · July 18, 2017, 11:31

None? Come one guys

ghorrocks · July 18, 2017, 18:45

This might explain why: https://www.cfd-online.com/Wiki/Ansy...ible_answer.3F

Your question is impossible to answer with no details. Please provide details of what you are trying to do, what results you are getting and what results you expect to get and then we might be able to answer you.

July 16, 2017, 09:35	Wall roughness and boundary layer (y+)	#1
gdimitris New Member Dim. G Join Date: May 2017 Posts: 29 Rep Power: 8	Hi guys, I am introducing surface roughness in my simulation to get more realistic results, however, I observed something odd, the boundary layer in the model with wall roughness is not captured very well. The vectors are longrer and the y+ has increased from about 0.3 to 8 (max values). Is there something wrong with my simulations or do I need to make the mesh denser around the blade to get better y+ and thus capture the boundary layer? Thank you in advance.

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July 18, 2017, 11:31		#2
gdimitris New Member Dim. G Join Date: May 2017 Posts: 29 Rep Power: 8	None? Come one guys

July 18, 2017, 18:45		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	This might explain why: https://www.cfd-online.com/Wiki/Ansy...ible_answer.3F Your question is impossible to answer with no details. Please provide details of what you are trying to do, what results you are getting and what results you expect to get and then we might be able to answer you.