Ansys FLUENT UDF - Velocity profile (of known values) across edge / surface

emmkell · October 20, 2011, 07:49

Hi

I have a known velocity profile, which i found from experimental testing. It is across a surface and I know the velocity values at 100 points across this surface.

Is it possible to create a UDF to assign these values to 100 points across an edge in Fluent (or say across a known distance with each of the 100 values spread equidistant across the edge)?

Would really appreciate any help, I am reading the UDF manual but it seems the profile UDF's all require an equation to assign the profile.

Thanks!

Emma

giuli@ · October 20, 2011, 08:39

Hi Emma

you can enter a velocity profile as velocity inlet b.c. . If your surface is a wall, the velocity there is zero..
Btw, why do you start your simulation from the results backwards and not the other way round (as it is usually done)..? maybe I didn't get your question!

cheers,

gg

tmulcahey3 · October 21, 2011, 13:12

Your best bet is to assign a curve fit to your data and use that equation in your velocity UDF. see DEFINE_PROFILE in the UDF manual for details. You could probably assign the points individually if the mesh geometry matches the distribution of your data points exactly, but that seems like a pain to do since you would have to assign each value individually.

October 20, 2011, 07:49	Ansys FLUENT UDF - Velocity profile (of known values) across edge / surface	#1
emmkell New Member Emma Join Date: Sep 2009 Posts: 17 Blog Entries: 1 Rep Power: 16	Hi I have a known velocity profile, which i found from experimental testing. It is across a surface and I know the velocity values at 100 points across this surface. Is it possible to create a UDF to assign these values to 100 points across an edge in Fluent (or say across a known distance with each of the 100 values spread equidistant across the edge)? Would really appreciate any help, I am reading the UDF manual but it seems the profile UDF's all require an equation to assign the profile. Thanks! Emma

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October 20, 2011, 08:39		#2
giuli@ New Member FlowLy Join Date: Aug 2010 Location: Germany Posts: 18 Rep Power: 15	Hi Emma you can enter a velocity profile as velocity inlet b.c. . If your surface is a wall, the velocity there is zero.. Btw, why do you start your simulation from the results backwards and not the other way round (as it is usually done)..? maybe I didn't get your question! cheers, gg

October 21, 2011, 13:12		#3
tmulcahey3 New Member Tom M Join Date: Oct 2011 Posts: 7 Rep Power: 14	Your best bet is to assign a curve fit to your data and use that equation in your velocity UDF. see DEFINE_PROFILE in the UDF manual for details. You could probably assign the points individually if the mesh geometry matches the distribution of your data points exactly, but that seems like a pain to do since you would have to assign each value individually.