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CFDesign and Static Pressure within Solids

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Old   August 17, 2010, 17:46
Question CFDesign and Static Pressure within Solids
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Was looking at a report prepared by a colleague in CFDesign V10 and noticed the "static pressure" cut plot showed a varying static pressure within a solid steel flow obstruction in an external flow system. I though this odd, and ran one of their examples myself, looked at the static pressure and while it is small, it is certainly non-zero within their solid copper device. I refined the mesh significantly and still same story, however the velocity magnitude plot is exactly zero within the steel obstruction (which it had better be - non molten steel is not known for having high velocity magnitudes)

Anyhow, my question is simply what is going on to see an internal static pressure on solids and why am I seeing this behavior...

Hopefully not too dumb of a question, I am far from a CFD expert - just past beginner with some software packages in my opinion.

Thanks
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Old   August 19, 2010, 12:46
Default Pressure sin Solids
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Dr. Richard R. Lange
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I am not a CFDesign user, but I would venture that it just has to do with the graphics and the plotting routines. There are pressures at the wall, and the plotting routine probably is taking values near the wall and extrapolating to the other side. The values in the solid are either zero or undefined.

This is easy to avoid with velocities, because if near wall values (such as the conservative values in CFX) are non-zero to enforce conservation of mass in near wall cells, you can just overwrite these with a wall condition of V=0, which you get from either knowing it is a solid or applying a boundary condition.
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Old   August 25, 2010, 19:59
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Derrek Cooper
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Rich is correct. It's just a graphics display that you are seeing. Static pressure is not computed ie (equals zero) in a solid for a flow problem
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