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velocity inlet using udf

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Old   May 5, 2012, 12:22
Wink velocity inlet using udf
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hilla tor
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i have an velocity inlet profile u(y)
but this profile isn't Analytical (i have an array u) how can I put it as a udf function?
the final result should be a u(y)u(t) so i can't use the regular profile at (define-> profiles)
thanks for the help
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Old   May 10, 2012, 00:37
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Patrick
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Quote:
Originally Posted by hillator View Post
i have an velocity inlet profile u(y)
but this profile isn't Analytical (i have an array u) how can I put it as a udf function?
the final result should be a u(y)u(t) so i can't use the regular profile at (define-> profiles)
thanks for the help
You can use a UDF with lots of IF statements. For example, if you have 4 mesh points in your inlet face at y=0,1,2,3 the UDF will be:

if y<3 then;
velocity=ArrayU(1)
if y<2 then;
velocity=ArrayU(2)
if y<1 then;
velocity=ArrayU(3)
if y<0 then;
velocity=ArrayU(4)

Obviously making this kind of UDF is best suited to a computer program if you have many mesh points, so you need to write a computer program to write your UDF for you

I think Fluent will interpolate the velocity profile if you don't have data for each meshpoint.
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