Wall roughness in FLuent 14.5

venkatesh92 · November 27, 2014, 04:40

Hello,

I am trying to introduce surface roughness in SST k-w model. I came across a paper by A.Hellesten & F.Menter, who proposed a modification to the eddy viscosity term to include surface roughness in terms of uniform sand grain roughness (K_s). Is it possible to write an UDF for just eddy viscosity and leave the rest of the model in tact? Or should I write the complete transport equations for this model?

Thanks

venkatesh92 · December 2, 2014, 05:37

Hello! Can someone help me with this? Would geometrically modelling the wall in CAD help? I am not too hopeful about this method though.

Thanks!

edoan · December 2, 2014, 09:11

In the wall boundary condition setting you can define a wall roughness (the default condition is smooth)... its very simple just input your value no UDF or geometry modification required.... is this what you Want?

venkatesh92 · December 3, 2014, 09:11

Thanks ethan, but that is possible only with k-epsilon models. If you choose k-omega or V2-f , you cant include it. Does someone have a solution to this problem?

November 27, 2014, 04:40	Wall roughness in FLuent 14.5	#1
venkatesh92 New Member Join Date: Nov 2014 Posts: 9 Rep Power: 11	Hello, I am trying to introduce surface roughness in SST k-w model. I came across a paper by A.Hellesten & F.Menter, who proposed a modification to the eddy viscosity term to include surface roughness in terms of uniform sand grain roughness (K_s). Is it possible to write an UDF for just eddy viscosity and leave the rest of the model in tact? Or should I write the complete transport equations for this model? Thanks

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December 2, 2014, 05:37		#2
venkatesh92 New Member Join Date: Nov 2014 Posts: 9 Rep Power: 11	Hello! Can someone help me with this? Would geometrically modelling the wall in CAD help? I am not too hopeful about this method though. Thanks!

December 2, 2014, 09:11		#3
edoan Member Ethan Doan Join Date: Oct 2012 Location: Canada Posts: 90 Rep Power: 13	In the wall boundary condition setting you can define a wall roughness (the default condition is smooth)... its very simple just input your value no UDF or geometry modification required.... is this what you Want?

December 3, 2014, 09:11		#4
venkatesh92 New Member Join Date: Nov 2014 Posts: 9 Rep Power: 11	Thanks ethan, but that is possible only with k-epsilon models. If you choose k-omega or V2-f , you cant include it. Does someone have a solution to this problem?