Inlet Velocity Profile UDF

buckngnr11 · May 18, 2020, 22:28

Hi, I'm trying to read in a .csv file to transfer velocity components and turbulence settings from a different simulation in another CFD solver. A long time ago I was able to import a .txt file to read in the profile. I'm trying to use a UDF now, with Define_Profile function. I found a template to follow, but the first issue I'm having is reading the array of data from the .csv file. Is there a better way to do this than the way I'm trying to do it? I attached a picture of the start of my code and the .csv file I need to read in.

Thx

vinerm · May 19, 2020, 02:18

A better way is not to use UDF. Use the text file as it is with a few minor changes. Put it in profile format and read it in Fluent. To use data in a file for boundaries, UDF is not required.

UDF has errors; it won't even compile because x, y, and z are being re-declared. And though file is being read, it is not being used.

homay95 · May 19, 2020, 06:00

i need a udf for slip wall
i want to use udf for setting this boundary condition:
us=B*(du/dy)
what should i do?

vinerm · May 19, 2020, 08:03

There are at least a couple of posts on Fluent forum where such a UDF is available.

homay95 · May 19, 2020, 10:48

can you please send the links for that posts to my mail?
homayoonsohrabi@yahoo.com

vinerm · May 19, 2020, 11:12

I suppose you commented on those posts, so, you should look at your own old posts to find those out. It would be easier to search that way.

Furthermore, you can expect better help if you write a UDF yourself instead of just searching for a pre-written one exactly matching your requirement. Someone might have it but it would take longer to find out who and then its on that person if he or she wants to share it or not.

buckngnr11 · May 19, 2020, 13:49

Thanks for the advice. I was hoping to import the .csv file without moving it to a text file, but it's not the end of the world to do so. Seems to be the easiest way

vinerm · May 19, 2020, 14:57

.csv and .txt are just extensions; both are text files.

zhangdongjie · January 6, 2021, 21:22

Quote:

Originally Posted by homay95

i need a udf for slip wall
i want to use udf for setting this boundary condition:
us=B*(du/dy)
what should i do?

How to load the temperature jump UDF in fluent? Is it directly loaded into the wall temperature

AlexanderZ · January 7, 2021, 03:10

Quote:

Originally Posted by zhangdongjie

How to load the temperature jump UDF in fluent? Is it directly loaded into the wall temperature

if you want to have temperature jump on the wall, you should apply it to the wall, for example using define_profile macro

May 19, 2020, 02:18	Better Way	#2
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 35	A better way is not to use UDF. Use the text file as it is with a few minor changes. Put it in profile format and read it in Fluent. To use data in a file for boundaries, UDF is not required. UDF has errors; it won't even compile because x, y, and z are being re-declared. And though file is being read, it is not being used. buckngnr11 likes this. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

May 19, 2020, 06:00	UDF for slip velocity and temperature jump	#3
homay95 Member Homayoon sohrabi Join Date: May 2020 Posts: 56 Rep Power: 5	i need a udf for slip wall i want to use udf for setting this boundary condition: us=B*(du/dy) what should i do?

May 19, 2020, 08:03	Slip Velocity	#4
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 35	There are at least a couple of posts on Fluent forum where such a UDF is available. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

May 19, 2020, 11:12	Old Posts	#6
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 35	I suppose you commented on those posts, so, you should look at your own old posts to find those out. It would be easier to search that way. Furthermore, you can expect better help if you write a UDF yourself instead of just searching for a pre-written one exactly matching your requirement. Someone might have it but it would take longer to find out who and then its on that person if he or she wants to share it or not. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

May 19, 2020, 14:57	CSV and TXT	#8
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 35	.csv and .txt are just extensions; both are text files. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

May 19, 2020, 10:48		#5
homay95 Member Homayoon sohrabi Join Date: May 2020 Posts: 56 Rep Power: 5	can you please send the links for that posts to my mail? homayoonsohrabi@yahoo.com

May 19, 2020, 13:49		#7
buckngnr11 Member j Join Date: Apr 2020 Posts: 34 Rep Power: 0	Thanks for the advice. I was hoping to import the .csv file without moving it to a text file, but it's not the end of the world to do so. Seems to be the easiest way

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
UDF velocity inlet sinusoidal profile	dka14	Fluent UDF and Scheme Programming	0	March 27, 2017 06:58
Problem with assigned inlet velocity profile as a boundary condition	Ozgur_	FLUENT	5	August 25, 2015 04:58
simpleFoam: Non-uniform mesh near inlet & outlet causes incorrect velocity profile?	Zaphod'sSecondHead	OpenFOAM Running, Solving & CFD	0	January 28, 2015 05:17
FSI- Pipe- uniform velocity profile inlet	Absy	Main CFD Forum	0	April 6, 2010 03:01
what the result is negatif pressure at inlet	chong chee nan	FLUENT	0	December 29, 2001 05:13