Quantifying Recirculation Region

ashtonJ · August 31, 2014, 23:50

Dear all,
I am looking for a method to quantify flow recirculation zone.
I have modelled blood flow in several arteries and need to compare the amount of recirculated flow regions in these arteries.
If anybody knows how to quantify the recirculation zone, please let me know.

Thanks
AshtonJ

flotus1 · September 3, 2014, 06:17

The end of a recirculation zone next to a wall is usually defined using the change of sign of the wall shear stress.

ashtonJ · July 12, 2015, 21:52

Thank Alex.

CFD-Post plots doesn't give you the direction of WSS (WSS values are always positive)

Do you know how to determine the direction of WSS in CFD-Post?

flotus1 · July 13, 2015, 04:25

You might be looking at the magnitude of the wall shear stress. In this case a local minimum with a value of zero (or very close to it) is equivalent for intrinsically two-dimensional setups like a backward facing step.

When I was talking about sign change, I was referring to the individual components of the wall shear stress vector
$\tau_{w,i} = \left. \mu \frac{\partial u_i}{\partial y} \right|_{y=0}$
where y is in normal direction of the wall.

August 31, 2014, 23:50	Quantifying Recirculation Region	#1
ashtonJ Senior Member Ashkan Javadzadegan Join Date: Sep 2010 Posts: 255 Rep Power: 16	Dear all, I am looking for a method to quantify flow recirculation zone. I have modelled blood flow in several arteries and need to compare the amount of recirculated flow regions in these arteries. If anybody knows how to quantify the recirculation zone, please let me know. Thanks AshtonJ

July 13, 2015, 04:25		#4
flotus1 Super Moderator Alex Join Date: Jun 2012 Location: Germany Posts: 3,399 Rep Power: 46	You might be looking at the magnitude of the wall shear stress. In this case a local minimum with a value of zero (or very close to it) is equivalent for intrinsically two-dimensional setups like a backward facing step. When I was talking about sign change, I was referring to the individual components of the wall shear stress vector $\tau_{w,i} = \left. \mu \frac{\partial u_i}{\partial y} \right\|_{y=0}$ where y is in normal direction of the wall. Last edited by flotus1; July 13, 2015 at 05:28.

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September 3, 2014, 06:17		#2
flotus1 Super Moderator Alex Join Date: Jun 2012 Location: Germany Posts: 3,399 Rep Power: 46	The end of a recirculation zone next to a wall is usually defined using the change of sign of the wall shear stress.

July 12, 2015, 21:52		#3
ashtonJ Senior Member Ashkan Javadzadegan Join Date: Sep 2010 Posts: 255 Rep Power: 16	Thank Alex. CFD-Post plots doesn't give you the direction of WSS (WSS values are always positive) Do you know how to determine the direction of WSS in CFD-Post?