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UDF for inlet velocity profile

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Old   January 15, 2013, 05:22
Default UDF for inlet velocity profile
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Francisco
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Hi guys,

I'm using a UDF for a velocity profile to define the atmospheric boundary layer in a 2D problem. I've used the attached c code as explained in the user manual, apparently it's interpreted properly but results don't show any influence on the profile, it appears to be just a uniform velocity at the inlet (see attached picture for 5s).

1) Which can be the problem? Is there something wrong in the code?

2) What will happen if I modify the ymax coord in the code so it's higher than the domains's ymax?

3) Also I would like to use a profile for the turbulence intensity (TI), but Fluent only allows me to use it for k and epsilon. Is there a way to use TI and Turbulent Length Scale (TLS) instead of applying the formulae for (TI,TLS)\Rightarrow(k,epsilon).

4) I will need to apply the same profile to a 3D case. It will be exactly the same in the x-y plane and constant in the z-direction. Can I use directly the same code? If not, what do I have to modify?

Thanks you all!
Attached Images
File Type: jpg Uprofile_keR_U10_Iu15_TLS0.001-1-5.000000.jpg (62.4 KB, 204 views)
Attached Files
File Type: c inlet_x_velocity.c (751 Bytes, 280 views)
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Old   October 6, 2015, 12:53
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Env
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Hello Bollonga: I have same problems as yours, and I see that you asked this question long time ago! so I assume you have found the answers although no one replied here. I appreciate if you could share what you found with me. My main problem is how to write a UDF to use a profile for TI of an inlet boundary condition.

If you have an example UDF, I appreciate if you share it here.

Thanks,
Env

Quote:
Originally Posted by Bollonga View Post
Hi guys,

I'm using a UDF for a velocity profile to define the atmospheric boundary layer in a 2D problem. I've used the attached c code as explained in the user manual, apparently it's interpreted properly but results don't show any influence on the profile, it appears to be just a uniform velocity at the inlet (see attached picture for 5s).

1) Which can be the problem? Is there something wrong in the code?

2) What will happen if I modify the ymax coord in the code so it's higher than the domains's ymax?

3) Also I would like to use a profile for the turbulence intensity (TI), but Fluent only allows me to use it for k and epsilon. Is there a way to use TI and Turbulent Length Scale (TLS) instead of applying the formulae for (TI,TLS)\Rightarrow(k,epsilon).

4) I will need to apply the same profile to a 3D case. It will be exactly the same in the x-y plane and constant in the z-direction. Can I use directly the same code? If not, what do I have to modify?

Thanks you all!
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Old   March 12, 2019, 11:12
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Quote:
Originally Posted by Bollonga View Post
Hi guys,

I'm using a UDF for a velocity profile to define the atmospheric boundary layer in a 2D problem. I've used the attached c code as explained in the user manual, apparently it's interpreted properly but results don't show any influence on the profile, it appears to be just a uniform velocity at the inlet (see attached picture for 5s).

1) Which can be the problem? Is there something wrong in the code?

2) What will happen if I modify the ymax coord in the code so it's higher than the domains's ymax?

3) Also I would like to use a profile for the turbulence intensity (TI), but Fluent only allows me to use it for k and epsilon. Is there a way to use TI and Turbulent Length Scale (TLS) instead of applying the formulae for (TI,TLS)\Rightarrow(k,epsilon).

4) I will need to apply the same profile to a 3D case. It will be exactly the same in the x-y plane and constant in the z-direction. Can I use directly the same code? If not, what do I have to modify?

Thanks you all!
Hi, did you solved your problem? Let me know if I can help.
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Old   June 28, 2021, 03:24
Default Turbulent boundary layer 3d problem
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Gutti Lokesh Kalyan
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Hello friends.

I am trying to use three velocity components code which is written in c language. Also, the Reynolds stress of R11, R21, R22, R33 was given to test the results. but I am getting wrong plots of u,v,w standard deviation, and UV Reynolds stress. I don't know what is the problem with this code. I am a beginner at coding. I guess the structure is wrong. I am using fluent software to run simulations.

Could anyone help me to solve the problem in the code is attached below?

Thanks in advance.
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File Type: c udf.c (20.0 KB, 4 views)
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Old   June 29, 2021, 04:40
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Alexander
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AlexanderZ will become famous soon enoughAlexanderZ will become famous soon enough
your code has 800+ line, I expect it will be hard to find person, who will debug this code instead of you

compilation log:
line(53) : warning C4716: 'sort' : must return a value
line(60) : warning C4715: 'findY' : not all control paths return a value


functions sort and findY could have some problems, check it
however, these warnings may not lead to errors.
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inclined flat plate, inlet, turbulence profile, udf, velocity profile

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