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-   -   Pulsatile blood flow (http://www.cfd-online.com/Forums/fluent/33161-pulsatile-blood-flow.html)

Duncan March 4, 2004 09:33

Pulsatile blood flow
 
My project is titled 'initial platelet adhesion in an axi-symmetric expansion tube, under pulsatile flow'. I was wondering if anyone knew the easiest way of incorporating pulsatile flow and initial platelet adhesion into the model. I assume for the blood flow it is a velocity profile but I don't know how to apply this for fluent

Duncan

paul March 9, 2004 13:50

Re: Pulsatile blood flow
 
Duncan,

There is an example in the Fluent UDF documentation that models a sinusoidal wave input. The last segment of Ch. 11.1 has the UDF text file that you will need. As a first approxiamtion a sine wave may be acceptable for the pulsatile nature of blood flow. Hope this helps

Paul

Duncan March 10, 2004 09:01

Re: Pulsatile blood flow
 
Thanks a lot I'll take a look and see how it goes Cheers, Duncan

amirokhovat September 8, 2011 14:26

Hi dear
what funcation you use for pulstile blood flow?
THANK VERY MUCH

mohammadkm October 10, 2011 05:21

I think it is
V=a(1+b*sin(w*t))
I'm no t sure.
best

hesamking March 23, 2012 14:23

help to set the inflow BC in CFX
 
1 Attachment(s)
i am doing a research on an aneurysm, I want to redo an
already done work to learn details of this work.
I don't know how I should set up the inlet velocity. I have the inlet velocity waveform graph from the paper, but I do not have any expression or equation which i can input into CFX. will you please guide me what I should do?
I am doing my study for an aneurysm at a bifurcation of a basilar artery. I have one inlet and two outlets? I also wanted to ask what B.C i should use for the outlet. In paper, I think it mentions Newmann B.C.
I have attached the picture of inflow waveform. I would really appreciate your kind help.
Regards,
Heasam

vix November 2, 2012 11:40

Quote:

Originally Posted by hesamking (Post 351162)
i am doing a research on an aneurysm, I want to redo an
already done work to learn details of this work.
I don't know how I should set up the inlet velocity. I have the inlet velocity waveform graph from the paper, but I do not have any expression or equation which i can input into CFX. will you please guide me what I should do?
I am doing my study for an aneurysm at a bifurcation of a basilar artery. I have one inlet and two outlets? I also wanted to ask what B.C i should use for the outlet. In paper, I think it mentions Newmann B.C.
I have attached the picture of inflow waveform. I would really appreciate your kind help.
Regards,
Heasam

Hey hesam

Did you manage to generate the inlet velocity for your particular graph. I am looking to do something similar and was wondering if you could help out.

Thanks!

ghost82 November 2, 2012 12:21

1 Attachment(s)
Quote:

Originally Posted by vix (Post 389909)
Hey hesam

Did you manage to generate the inlet velocity for your particular graph. I am looking to do something similar and was wondering if you could help out.

Thanks!

Hi,
you can write a profile, by "linearizing" your curve, as in the attached picture.
This is just an idea.

The profile should be as following (following values must be refined..:))

Code:

((profile transient 20 0)
(time 0 0.01 0.07 0.08 0.11 0.15 0.2 0.23 0.32 0.37 0.43 0.5 0.55 0.67 0.7 0.75 0.79 0.87 0.9 1.0)
(velocity 0.37 0.36 0.61 0.61 0.57 0.47 0.4 0.37 0.37 0.36 0.36 0.38 0.38 0.35 0.35 0.36 0.36 0.35 0.35 0.36))

20 are the number of points, 0 means non periodic.
Then write time points and corresponding velocity points.

Daniele

hesamking November 2, 2012 12:46

Quote:

Originally Posted by vix (Post 389909)
Hey hesam

Did you manage to generate the inlet velocity for your particular graph. I am looking to do something similar and was wondering if you could help out.

Thanks!

Hey Vix,
Actually I did.
Use a software like "Dagra" or any other to extract the points out of your curve and save them in an excel file.
then using MATLAB "cftool" Toolbox or "Curve Expert" to fit a polynomial on the data. then use FFT in MATLAB with that polynomial as your function to get the Fourier Coefficients out of the program. If you want, I can send you the program. Send me your email.
After getting the Fourier Coeff. you will make a CCL file in FORTRAN language and import it into CFX Expressions. In this way, you will get a periodic (pulsatile) inflow velocity or pressure.
Good Luck,
Hesam

vix November 3, 2012 13:12

Thanks for your replies Daniele and Hesam.

I already have the velocity values against time now .

Hesam my email is vvmehta@gmail.com - would really appreciate if you could send it so I can figure out what to do next.

Also, I am using Fluent not CFX and will need to make a UDF in C language just to let you know. Would that change much ?

Many thanks

hesamking November 3, 2012 13:33

Quote:

Originally Posted by vix (Post 390057)
Thanks for your replies Daniele and Hesam.

I already have the velocity values against time now .

Hesam my email is vvmehta@gmail.com - would really appreciate if you could send it so I can figure out what to do next.

Also, I am using Fluent not CFX and will need to make a UDF in C language just to let you know. Would that change much ?

Many thanks

Hey Vix,
Actually It's different. As you said it should be in C language. but I have a code for inflow velocity for that in C language too that will send it to your mail.
Also you may experience some problems when you want to upload UDF in Fluent as you should start up Fluent using Windows Prompt Command?
Good luck

ami1991 April 10, 2013 12:17

Quote:

Originally Posted by hesamking (Post 389922)
Hey Vix,
Actually I did.
Use a software like "Dagra" or any other to extract the points out of your curve and save them in an excel file.
then using MATLAB "cftool" Toolbox or "Curve Expert" to fit a polynomial on the data. then use FFT in MATLAB with that polynomial as your function to get the Fourier Coefficients out of the program. If you want, I can send you the program. Send me your email.
After getting the Fourier Coeff. you will make a CCL file in FORTRAN language and import it into CFX Expressions. In this way, you will get a periodic (pulsatile) inflow velocity or pressure.
Good Luck,
Hesam

sir,
I am a final year engg student and i am doing a project on the same topic. I have not figured out any program to get a pulsalite blood flow... could you kindly send me the same??? my email id amithaprabhakar@yahoo.co.in


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