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-   -   How to set a time varying velocity field as a BC? (http://www.cfd-online.com/Forums/openfoam-pre-processing/62648-how-set-time-varying-velocity-field-bc.html)

Mikro March 16, 2009 08:10

How to set a time varying velocity field as a BC?
 
Hello,

I'm trying to simulate blood flow in a arterie and i want to set the pulsating velocity as a boundary condition at the inlet. As i'm new to OpenFOAM and my C++ knowledge is limited at best, i was hoping that somebody here could point me to the right direction.

I was thinking of using the timevaryinguniformfixedvalue, and read from a file, like "inlet.dat" or smth like that. however I'm not sure on how to make it read a field for each timestep, instead of a vector, so any help in that department is really appreciated.

Thanks in advance.

santos March 16, 2009 08:28

Hi,

I think this might help you:

http://openfoamwiki.net/index.php/OscillatingFixedValue

Regards,
Jose Santos

Mikro March 16, 2009 09:39

Quote:

Originally Posted by santos (Post 209601)
Hi,

I think this might help you:

http://openfoamwiki.net/index.php/OscillatingFixedValue

Regards,
Jose Santos

I thought about oscillating fixed value before, but i want to use the womersley solution to describe the velocity (heart rate) and i'm not sure i can do that using oscillatingfixed value (i figured that i would need to edit the oscillatingfixedvalue.c file to use the womersley eq instead of the one thats used), so i descided to write a small application that would give me the velocity field for a number of timesteps and output it in a file instead. And that is why i was wondering how, or perhaps even If, i could use timevaryinguniformfixedvalue.

chris_sev March 17, 2009 11:13

Hi Mikro,

I am also calculating blood flow in arterie.

I wonder which viscosity model do you use?

Regards,
Chris

dmoroian March 17, 2009 13:57

If you want the timeVaringUniformFixedValue, then check this thread:

http://www.cfd-online.com/Forums/ope...tml#post190753

and for the file format:

http://www.cfd-online.com/Forums/ope...tml#post190756

Dragos

Mikro March 19, 2009 05:38

Quote:

Originally Posted by chris_sev (Post 209781)
Hi Mikro,

I am also calculating blood flow in arterie.

I wonder which viscosity model do you use?

Regards,
Chris

I plan to use several and compare the diffrences, however i'm setting upp a newotonian case first, and right now the inlett velocity is giving me a pain in the ***... :)


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