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-   -   No Slip Boundary Condition (http://www.cfd-online.com/Forums/cfx/86038-no-slip-boundary-condition.html)

ashtonJ March 12, 2011 20:30

No Slip Boundary Condition
 
Dear All

I simulated a fluid flow in a pipe. When I considered the velocity vectors in CFD Post I found out that on the pipe wall axial velocity is not zero while I used no-slip boundary condition on the wall. Does anybody know why?

Regards,
AshtonJ

ghorrocks March 13, 2011 06:52

Look in the documentation for an explanation of hybrid and conservative variables. That is why the velocity at the wall appears to not be zero.

But rest assured that CFX is correctly applying the no slip boundary with zero velocity walls.

ashtonJ May 16, 2011 21:47

Hi

I want to plot axial velociy versus radius at the throat of a constricted pipe. I changed the axial velocity from conservative to hybrid variable however when I plot axial velocity, its boundary values are not zero. Do you know how I can plot the axial velocity with zero values on the boundaries.

Regards,
ashtonJ


Quote:

Originally Posted by ghorrocks (Post 299172)
Look in the documentation for an explanation of hybrid and conservative variables. That is why the velocity at the wall appears to not be zero.

But rest assured that CFX is correctly applying the no slip boundary with zero velocity walls.


ghorrocks May 17, 2011 19:05

Is the point at the boundary exactly on the boundary?

The hybrid values should have zero at the wall. If not then you have done something wrong.

ashtonJ May 17, 2011 19:07

Thank you very much. You are right my point was not exectly on the wall.

Regards,
ashtonJ

Quote:

Originally Posted by ghorrocks (Post 308045)
Is the point at the boundary exactly on the boundary?

The hybrid values should have zero at the wall. If not then you have done something wrong.



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