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-   -   Boundary details, free slip or no slip? (http://www.cfd-online.com/Forums/cfx/25354-boundary-details-free-slip-no-slip.html)

Tiago March 3, 2008 08:00

Boundary details, free slip or no slip?
 
Hi!

In CFX-PRE -- boundary domain- default/Boundary details/ wall influence on flow, there are two options :

-No Slip -Free Slip

My simulation type is in regime transient.

And i am trying to simulate a tank with water inside.

I must put No slip or free slip? What is the difference between these parameters?

Thanks one more time!

Tiago.

Gen March 3, 2008 08:58

Re: Boundary details, free slip or no slip?
 
No slip I.e. Fluid Velocity=0 on the walls Free slip = no friction between fluid and wall

Subha March 3, 2008 09:36

Re: Boundary details, free slip or no slip?
 
Hai Tiago,

Whether the water in the tank static or Dynamic? Are you doing a open cavity problem?

Regards,

Subha.

Tiago March 3, 2008 12:22

Re: Boundary details, free slip or no slip?
 
Hi! the water in the tank is dynamic.

And the tank is open in top!

Itīs better use no slip?or free slip?


Glenn Horrocks March 3, 2008 17:34

Re: Boundary details, free slip or no slip?
 
Hi,

Almost certainly you want the water phase to be no slip, but for some simulations you may wish the air phase to be free slip so you don't get wall function problems if the air drag is insignificant in the simulation. I think the CFX tutorials talk about this issue.

Glenn Horrocks

mohamad3564 August 20, 2013 22:54

free slip boundary condition for gas
 
Hello

I study gas- liquid bubble column. and I use free slip boundary condition for gas base on previous study. I want to understand why I have to use this
boundary condition for gas.
Thank you.


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