CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   interfacial shear stress (http://www.cfd-online.com/Forums/fluent/74887-interfacial-shear-stress.html)

duaiduaihu April 10, 2010 23:05

interfacial shear stress
 
my work is focused on the water-oil stratified flow.
as the interfacial is curved and the shear stress must be tangent to the interface, it is a little difficult fo me to get the interfacial shear stress in the flowing direction per unit length .

your reply will help me out. hoping for everyone's reply! Thanks

jack1980 April 11, 2010 11:58

Hi,

Perhaps you can try the following. Assuming your running a VOF method.

Surface -> Iso-Surface ...
Surface of Constant: Phases ... Volume Fraction
Iso-Values: 0.5
From Zones: fluid
New Surface Name: interface (or whatever you like...)

Display -> Countours
Contours of: Derivatives ... Strain Rate
Surfaces: interface
(perhaps you will have to turn of Auto Range and enter a proper Min and Max)

The shear stress should simply be related to this strain rate by the viscosity. Although I can't figure out which viscosity you should use here, since the phase is "mixture". A quick solution might be to - temporarily - adjus both viscosities under Define -> Materials ...

Anyway, you would have to look into this shear-stress / strain-rate relation.

Hope this helps, good luck!

duaiduaihu April 12, 2010 04:21

Quote:

Originally Posted by jack1980 (Post 254180)
Hi,

Perhaps you can try the following. Assuming your running a VOF method.

Surface -> Iso-Surface ...
Surface of Constant: Phases ... Volume Fraction
Iso-Values: 0.5
From Zones: fluid
New Surface Name: interface (or whatever you like...)

Display -> Countours
Contours of: Derivatives ... Strain Rate
Surfaces: interface
(perhaps you will have to turn of Auto Range and enter a proper Min and Max)

The shear stress should simply be related to this strain rate by the viscosity. Although I can't figure out which viscosity you should use here, since the phase is "mixture". A quick solution might be to - temporarily - adjus both viscosities under Define -> Materials ...

Anyway, you would have to look into this shear-stress / strain-rate relation.

Hope this helps, good luck!

hi ack1980!
Thanks for you reply!This will help me a lot!
what I want to know more is the integration of the shear stress of the interface(the dotted line )in the X direction.we can get the shear stress of each cell, but how to get the direction of the shear stress, as it is different of the shear stress direction of each cell, how to get the integration of the shear stress alone the interface(the dotted line)in the X direction. I think UDF might be used.
Hoping for your reply! thanks..

http://fmn.xnimg.cn/fmn036/20100412/...0488f52d12.jpg /

jack1980 April 12, 2010 04:39

I'm afraid the image is unavailable

duaiduaihu April 14, 2010 03:44

Quote:

Originally Posted by jack1980 (Post 254248)
I'm afraid the image is unavailable

hi jack1980,thanks for your kindness.would you please tell me your email address.it would be convenient for me to describe my problem clear!

my email address is daozhenxu@hotmail.com


All times are GMT -4. The time now is 23:57.