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Old   March 12, 2011, 20:30
Question No Slip Boundary Condition
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Ashkan Javadzadegan
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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?

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AshtonJ
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Old   March 13, 2011, 06:52
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Glenn Horrocks
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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.
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Old   May 16, 2011, 21:47
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Ashkan Javadzadegan
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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


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Originally Posted by ghorrocks View Post
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.
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Old   May 17, 2011, 19:05
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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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Old   May 17, 2011, 19:07
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Ashkan Javadzadegan
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Thank you very much. You are right my point was not exectly on the wall.

Regards,
ashtonJ

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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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