time dependent BC with fully developed velocity profile

susheil · June 22, 2010, 14:13

I am trying to simulate a pulsatile flow through a blood vessel. For doing this I created a profile file (*.prof) to generate a pulse required and applied this as a velocity-BC at the inlet. But this BC is a constant spatially.

For my purpose we would need a velocity pulse which is also fully developed. In other words, The how to apply a BC which varies both with respect to time and with respect to space.

Thanks.

jack1980 · June 22, 2010, 17:36

What a nice problem.

You can do this quite easily using a user defined function (UDF). This means you will have to write a very short .c file and then compile it from FLUENT. After that you can use it as a boundary condition. It is quite possible to multiply a fully developed parabolic profile with a time dependent sine. Or whatever you want really.

Have a look at: http://www.hipecc.wichita.edu/pdfs/fludf.pdf

jack1980 · June 22, 2010, 17:44

And then check the DEFINE_PROFILE for a velocity profile. If I remember correctly the function CURRENT_TIME should give the physical time you will need.

Good luck!

susheil · June 23, 2010, 10:43

Thanks,

The problem I am facing is that inlet in my model is not circular it is an irregular shape since this is blood vessel problem.

jack1980 · June 24, 2010, 08:44

I'm afraid I can't help you there. Fluent can use an experimentally determined inflow profile, but I don't think this can be time dependent. There must be some smart way to do this, hopefully somebody else knows how?

Good luck!

susheil · June 24, 2010, 09:27

Thanks Jack. I will try to figure it out. Will post If i find out.

milasko · December 20, 2012, 05:41

Hi susheil,

I am working on a pulsatile flow through aorta. Have you solved how to input experimentally determined inflow profile which is time dependent?

June 22, 2010, 14:13	time dependent BC with fully developed velocity profile	#1
susheil New Member Susheil Uthamaraj Join Date: Jun 2010 Posts: 4 Rep Power: 14	I am trying to simulate a pulsatile flow through a blood vessel. For doing this I created a profile file (*.prof) to generate a pulse required and applied this as a velocity-BC at the inlet. But this BC is a constant spatially. For my purpose we would need a velocity pulse which is also fully developed. In other words, The how to apply a BC which varies both with respect to time and with respect to space. Thanks.

June 24, 2010, 09:27	Thanks	#6
susheil New Member Susheil Uthamaraj Join Date: Jun 2010 Posts: 4 Rep Power: 14	Thanks Jack. I will try to figure it out. Will post If i find out.

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June 22, 2010, 17:36		#2
jack1980 Senior Member Jouke de Baar Join Date: Oct 2009 Posts: 126 Rep Power: 15	What a nice problem. You can do this quite easily using a user defined function (UDF). This means you will have to write a very short .c file and then compile it from FLUENT. After that you can use it as a boundary condition. It is quite possible to multiply a fully developed parabolic profile with a time dependent sine. Or whatever you want really. Have a look at: http://www.hipecc.wichita.edu/pdfs/fludf.pdf

June 22, 2010, 17:44		#3
jack1980 Senior Member Jouke de Baar Join Date: Oct 2009 Posts: 126 Rep Power: 15	And then check the DEFINE_PROFILE for a velocity profile. If I remember correctly the function CURRENT_TIME should give the physical time you will need. Good luck!

June 23, 2010, 10:43		#4
susheil New Member Susheil Uthamaraj Join Date: Jun 2010 Posts: 4 Rep Power: 14	Thanks, The problem I am facing is that inlet in my model is not circular it is an irregular shape since this is blood vessel problem.

June 24, 2010, 08:44		#5
jack1980 Senior Member Jouke de Baar Join Date: Oct 2009 Posts: 126 Rep Power: 15	I'm afraid I can't help you there. Fluent can use an experimentally determined inflow profile, but I don't think this can be time dependent. There must be some smart way to do this, hopefully somebody else knows how? Good luck!

December 20, 2012, 05:41		#7
milasko New Member Marko Milasinovic Join Date: Apr 2011 Posts: 23 Rep Power: 14	Hi susheil, I am working on a pulsatile flow through aorta. Have you solved how to input experimentally determined inflow profile which is time dependent?