UDF generation for pulsatile flow from sinusoidal wave

harry93 · July 13, 2021, 07:21

Hello CFD wizards,

I am working on patient specific AVF Geometry, and I want to use the sinusoidal wave (Inlet mass flow rate) for pulsatile blood flow as inlet boundary condition, which is attached to this thread for reference. How do I create the UDF from this wave ?

Thank you

Regards

Hari

pakk · July 13, 2021, 12:28

Do you have an equation for this pulse?

harry93 · July 13, 2021, 12:53

No sir, I have only that waveform figure. Please let me know, how can I proceed further from this waveform to create a UDF

Thank you

AlexanderZ · July 13, 2021, 23:57

depends on how long your simulation will be :
1. you may use transient profile
Inlet Speed
https://www.ozeninc.com/tech-tip-flu...text-file-udf/
2. in case you are going to have long simulation you may try to use UDF:
a. divide your graph to some parts and extract equations for each
b. read your graph as a table and interpolate data between points

harry93 · July 14, 2021, 02:28

Hello sir,

Thanks for your inputs. I've tried the 1st method i.e. to create the .txt file with X and Y variables. However, I would like to try using UDF rather than .txt file. Can you elaborate the points 2a and 2b ?

Thank you

July 13, 2021, 12:28		#2
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 26	Do you have an equation for this pulse? __________________ "The UDF library you are trying to load (libudf) is not compiled for parallel use on the current platform" is NOT the error after compiling. It is the error after loading. To see compiler errors, look at your screen after you click "build".

July 13, 2021, 23:57		#4
AlexanderZ Senior Member Alexander Join Date: Apr 2013 Posts: 2,363 Rep Power: 34	depends on how long your simulation will be : 1. you may use transient profile Inlet Speed https://www.ozeninc.com/tech-tip-flu...text-file-udf/ 2. in case you are going to have long simulation you may try to use UDF: a. divide your graph to some parts and extract equations for each b. read your graph as a table and interpolate data between points harry93 likes this. __________________ best regards ****************************** press LIKE if this message was helpful

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July 13, 2021, 12:53		#3
harry93 New Member HARIREDDY Join Date: Jul 2021 Posts: 4 Rep Power: 4	No sir, I have only that waveform figure. Please let me know, how can I proceed further from this waveform to create a UDF Thank you

July 14, 2021, 02:28		#5
harry93 New Member HARIREDDY Join Date: Jul 2021 Posts: 4 Rep Power: 4	Hello sir, Thanks for your inputs. I've tried the 1st method i.e. to create the .txt file with X and Y variables. However, I would like to try using UDF rather than .txt file. Can you elaborate the points 2a and 2b ? Thank you