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Old   December 19, 2013, 12:17
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Ke Wu
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Hi

This is a parabolic inlet profile written in UDF

Can anybody interpret each line into words?

I couldn't understand all of them

Many thanks
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Old   December 19, 2013, 13:34
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Which lines are causing you such a headache?
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Old   December 20, 2013, 06:15
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Quote:
Originally Posted by Zaktatir View Post
Which lines are causing you such a headache?
Hi Zaktatir

Thanks for your concern

For x[1] in equation of y, I think the domain is assumed to be from 0 to a positive value, isn't it? In other case, for example, the domain could be between -2 and 2

How the equations of y and F_profile been derived?
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Old   December 20, 2013, 06:52
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X is any array or vector holding your coordinates. In C we enumerate starting from 0 that means x[1] will be you y-coordinate x[0] your x-coordinate, x[2] your z-coordinate.

Then you apply F_Profile where you put your formula or your law in that case this velocity profile. Why F_Profile because your making an input to a boundary condition that means your law or your function should apply to the faces localized on that boundary
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Old   December 20, 2013, 07:01
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Quote:
Originally Posted by Zaktatir View Post
X is any array or vector holding your coordinates. In C we enumerate starting from 0 that means x[1] will be you y-coordinate x[0] your x-coordinate, x[2] your z-coordinate.

Then you apply F_Profile where you put your formula or your law in that case this velocity profile. Why F_Profile because your making an input to a boundary condition that means your law or your function should apply to the faces localized on that boundary
Yes, I know x[1] stands for y coordinate

My point is, for example, we got a pipe with diameter in 1m, will the value of x[1] coordinate be input to equation of y from bottom to top, from top to bottom or from middle to both sides?
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Old   December 20, 2013, 07:04
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it will scan your y in positive y direction
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Old   December 20, 2013, 07:38
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and it will handle the faces of the cells as ordered in the matrix since we are using unstructured meshes
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Old   October 30, 2014, 00:47
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To Zaktatir.
Code:
 it will scan your y in positive y direction
Are you comment fully?
My mean: y be scan from 0. to...?
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Old   October 30, 2014, 04:53
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It will not 'scan' anything, I think you are thinking in the wrong way.

You write the code for the profile, and add it as a boundary condition to a surface (let's call it surface A). During the calculation, Fluent will at some point need to put a velocity to a cell face from surface A. It then asks the UDFs that you wrote: "which velocity should I give to the cell face with coordinates x[0],x[1],x[2]?"

The UDF does not scan, or define the order in which the cells are accessed. Fluent does that. And for a properly written UDF, the order in which that happens should not matter for the result.
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Old   October 30, 2014, 09:19
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To pakk
Thanks for your reply, i try to think your hehp
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