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Pulsatile Womersley velocity profile

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Old   August 22, 2011, 08:31
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Daniel
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Quote:
Originally Posted by liguifan View Post
Did you successfully implement the Womersley pulsatile inlet flow using u(r,t) = exp(z*t) * (1 - J0(z*r) / J0(z) ) where z is complex number?
Not yet, I'm working on it

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Originally Posted by liguifan View Post
I am working on the same thing as well. Where is the A/z*rho*w term gone?
I just skiped it here, for clarity. It's just a constant factor...

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Originally Posted by liguifan View Post
They use womersley inlet condition with womersley number 7...
I got a parabolic velocity profile pulse with time. But the velocity profile seem to be symmetrical, which like a sin function across 1s ( time period )...
The Womersley Solution is for oscillatory flow, not pulsatile...
The pressure ansatz is harmonic, and so is the velocity...
For systolic wave forms you might find something helpful in the papers from METTE OLUFSEN...

Cheers
Daniel
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Old   August 22, 2011, 08:33
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Quote:
Originally Posted by liguifan View Post
Did you successfully implement the Womersley pulsatile inlet flow using u(r,t) = exp(z*t) * (1 - J0(z*r) / J0(z) ) where z is complex number?
Not yet, I'm working on it

Quote:
Originally Posted by liguifan View Post
I am working on the same thing as well. Where is the A/z*rho*w term gone?
I just skiped it here, for clarity. It's just a constant factor...

Quote:
Originally Posted by liguifan View Post
They use womersley inlet condition with womersley number 7...
I got a parabolic velocity profile pulse with time. But the velocity profile seem to be symmetrical, which like a sin function across 1s ( time period )...
The Womersley Solution is for oscillatory flow, not pulsatile...
The pressure ansatz is harmonic, and so is the velocity...
For systolic wave forms you might find something helpful in the papers from METTE OLUFSEN...

Cheers
Daniel
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Old   October 11, 2011, 09:00
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Michael Stiehm
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Hallo,

I am very interested in oscillating and pulsatile inletBC, so this is a great thread...thanks for that.

But I have two questions:

1: Where did you get the Womersley Solution for the real part (post 16 and 17)?
2: When you have got this solution, is there still an need to solve the basic womersley solution with bessel function for complex numbers? Because the real part solution looks very nice!!

Thanks a lot

Michael

Last edited by miael; October 12, 2011 at 11:14.
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Old   November 14, 2011, 05:09
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Quote:
Originally Posted by miael View Post
Hallo,

I am very interested in oscillating and pulsatile inletBC, so this is a great thread...thanks for that.

But I have two questions:

1: Where did you get the Womersley Solution for the real part (post 16 and 17)?
2: When you have got this solution, is there still an need to solve the basic womersley solution with bessel function for complex numbers? Because the real part solution looks very nice!!

Thanks a lot

Michael
Hi Michael,
the shown equation is derived for a 2D channel and not for a 3D pipe. Although, you have nice pulsatile effects the flow rate is a sinus if you integrate it. to get a flow rate which composes of multiple sinus and cosinus functions, the complex womersley equation is necessary.
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Old   March 11, 2012, 16:37
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juanjo rivera
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Nihil,

Are you finished the implementation of the Womersley BC for velocity?. Can you show one example? I am interesting to implement it but in function of flow rate, not pressure gradient.
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Old   March 19, 2012, 10:13
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Michael Stiehm
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Hello Juanjo,

perhabs I can help you with your womersley-problem. I used an octave-routine to calculate the womersley-profile. There you have no problem with komplex bessel functions.
So you can calculate your velocity field for every time step you wanna use. Additional you have to create a points file (see tutorial) and then use the BC timeVaryingMappedFixedValue.
I got good results with that.

Hope I could help.

Michael
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Old   June 23, 2012, 23:42
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Guifan Li
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Quote:
Originally Posted by miael View Post
Hello Juanjo,

perhabs I can help you with your womersley-problem. I used an octave-routine to calculate the womersley-profile. There you have no problem with komplex bessel functions.
So you can calculate your velocity field for every time step you wanna use. Additional you have to create a points file (see tutorial) and then use the BC timeVaryingMappedFixedValue.
I got good results with that.

Hope I could help.

Michael
Hi Michael,

I am working on the Womersley-problem for a while and I still didn't work out a good solution.

It sounds like you put the Womersley equation with complex bessel function into octave which is quite amazing. But how do you store the data ( velocity at different location for a 3D case)?

Btw, did you use the same equation below?


Thanks
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Old   June 25, 2012, 05:10
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Michael Stiehm
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Hello,

yes this is the equation I use. If you want to calculate the womersley-profile in octave you need the function besselj(0,...) for the complex bessel-function. So you get the womersley-profile u(r,t) for a 2D case. Because of axis-symmetric condition you can use the relationship r=sqrt(x^2+y^2) to calculate the 3D velocity field.
As inlet BC I use timeVaryingMappedFixedValue therefore a file called points is required which contains the coordinates and for every time step you need a velocity file which contains the velocity field regarding to the "point" file.

Regards

Michael
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