derivative for 2D axisymetric model

tsi07 · April 3, 2012, 09:46

Hi,

I'm trying to write a UDF which use derivative in a 2D axisymetrical model.

I wonder if there is a command like "C_DUDX" for Radial an Axial velocity which get back that velocities for the concerning cell.

Thanks for your answer !!

tsi07 · April 3, 2012, 11:06

Maybe it's the same thing and Fluent know that when I write C_DUDX, I want the axial-velocity derivative for x (the axial variable).

What do you think ?

tsi07 · April 5, 2012, 13:33

I don't have any answer from users

My udf doesn't give an error message, but I don't have what I want as result from the post process. So there is a problem and I wonder if it's from the command C_DUDX used to take the axial velocity derivative for x.

Can someone help me to know how can I make a variable with the name "new_velocity" as the axial-velocity for example?
The idea is to compare my new variable(make with the command C_U) with the real axial velocity?

Thanks !!

April 3, 2012, 09:46	derivative for 2D axisymetric model	#1
tsi07 Member Join Date: Mar 2012 Location: USA Posts: 33 Rep Power: 14	Hi, I'm trying to write a UDF which use derivative in a 2D axisymetrical model. I wonder if there is a command like "C_DUDX" for Radial an Axial velocity which get back that velocities for the concerning cell. Thanks for your answer !!

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April 3, 2012, 11:06		#2
tsi07 Member Join Date: Mar 2012 Location: USA Posts: 33 Rep Power: 14	Maybe it's the same thing and Fluent know that when I write C_DUDX, I want the axial-velocity derivative for x (the axial variable). What do you think ?

April 5, 2012, 13:33		#3
tsi07 Member Join Date: Mar 2012 Location: USA Posts: 33 Rep Power: 14	I don't have any answer from users My udf doesn't give an error message, but I don't have what I want as result from the post process. So there is a problem and I wonder if it's from the command C_DUDX used to take the axial velocity derivative for x. Can someone help me to know how can I make a variable with the name "new_velocity" as the axial-velocity for example? The idea is to compare my new variable(make with the command C_U) with the real axial velocity? Thanks !!