Modeling internal flow with normal velocities on walls- permeable walls

AliMadayen · April 27, 2014, 08:07

Hi everyone.

I'm trying to simulate blood flow in a vessel, where the boundary condition on wall for u is no slip, but for v is a constant definite value. In other words, wall is permeable in y direction. How can I apply this kind of boundary to my problem in CFX?

Tnx for your help

ghorrocks · April 27, 2014, 19:27

I presume you mean u is in the tangential direction and v is in the normal direction.

The easiest way of doing this would seem to be a normal no-slip wall with a mass source/sink applied to the wall which gobbles up fluid at your prescribed rate.

AliMadayen · April 27, 2014, 19:35

Tnx for your reply
your assumption is correct.
But now the question is what is the relation between source/sink intensity and the normal velocity?
Question is posed regarding that the problem specifies the normal velocity on the wall, and nothing more.

ghorrocks · April 27, 2014, 19:55

Make the magnitude of the mass sink a function of the wall shear stress. I would not make it a function of normal velocity as it will then be mesh dependent.

AliMadayen · April 27, 2014, 20:05

Real Smart.
I will try it for sure

AliMadayen · April 27, 2014, 20:06

Real smart, I will try it for sure
Thanks a lot, friend.

April 27, 2014, 08:07	Modeling internal flow with normal velocities on walls- permeable walls	#1
AliMadayen New Member Ali Madayen Join Date: Apr 2014 Posts: 22 Rep Power: 12	Hi everyone. I'm trying to simulate blood flow in a vessel, where the boundary condition on wall for u is no slip, but for v is a constant definite value. In other words, wall is permeable in y direction. How can I apply this kind of boundary to my problem in CFX? Tnx for your help

April 27, 2014, 19:27		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	I presume you mean u is in the tangential direction and v is in the normal direction. The easiest way of doing this would seem to be a normal no-slip wall with a mass source/sink applied to the wall which gobbles up fluid at your prescribed rate. dengdeng likes this.

April 27, 2014, 19:55		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	Make the magnitude of the mass sink a function of the wall shear stress. I would not make it a function of normal velocity as it will then be mesh dependent. AliMadayen likes this.

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April 27, 2014, 19:35		#3
AliMadayen New Member Ali Madayen Join Date: Apr 2014 Posts: 22 Rep Power: 12	Tnx for your reply your assumption is correct. But now the question is what is the relation between source/sink intensity and the normal velocity? Question is posed regarding that the problem specifies the normal velocity on the wall, and nothing more.

April 27, 2014, 20:05		#5
AliMadayen New Member Ali Madayen Join Date: Apr 2014 Posts: 22 Rep Power: 12	Real Smart. I will try it for sure

April 27, 2014, 20:06		#6
AliMadayen New Member Ali Madayen Join Date: Apr 2014 Posts: 22 Rep Power: 12	Real smart, I will try it for sure Thanks a lot, friend.