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-   -   How to read results values on nodes? (http://www.cfd-online.com/Forums/cfx/73031-how-read-results-values-nodes.html)

Felipe Matos February 24, 2010 22:07

How to read results values on nodes?
 
Hi
I'm starting at the Ansys CFX and i would like to know how to read the results at a specifc node. I've tried use the command "cfx5interp" at the command line (windows) but a message apeared that this a invalid command. Is there any way I can read this values inside the CFX-Post?

Thanks

ghorrocks February 25, 2010 01:41

Use a command editor launched off the CFX launcher. Then it will have the paths to the executables in it. If you use a normal commadn window you have to specify the full path to the executables.

Felipe Matos February 26, 2010 13:16

I managed to usa the interpolator correctly thanks.
But I wonder if there is another command that i can choose the node itself, like node #14, and see the results, instead choose a location (x,y,z). Does this command exist?

ghorrocks February 28, 2010 18:46

Why do you want a specific node rather than a location?

Felipe Matos February 28, 2010 22:18

Cause i want to make sure that the condition that i'm aplying in a boundary, like pressure, is really being followed.

My problem is this: i'm simullating a simple cylindrical pipe (2m diameter, 20m lenght). I'm putting a velocity condition in the inlet (a very low value for laminar regime), pressure condition at the outlet (0 Pa - absolute pressure) and no slip wall. The problem is: when I see the results, the pressures at the outlet ARE NOT 0 Pa as I commanded as boundary conditions - they are different from 0, and even negative (impossible, cause I'm working with absolute pressures). That's why I wanted to make sure that the nodes at the outlets were zero Pa, but I think they are not.

Should I create a new topic for this problem?

ghorrocks March 1, 2010 00:06

Have a read of the documentation. The default behaviour for an outlet is to define the total pressure for flow exitting the domain. This will mean the static pressure will be less than your specified pressure.

Also be aware that some boundary options use pressure averaging over the surface. This can also make the pressure vary over the patch.

And finally a zero absolute pressure condition cannot exist. It works in incompressible flow where the pressure can do whatever it likes - pressure is unbounded so it can go as negative as it wants.


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