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Old   April 3, 2009, 11:07
Default defining new expressions
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Mattia
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Dear all,

good morning.

I am simulating the flow within the diffuser of a centrifugal compressor and I'd like to post-process some properties (static pressure recovery coefficient, total pressure loss coefficient, efficiencies...) which are not available by default. They are of course functions of variables which are available in CFX-Post (like pressures, temperatures, velocities...).

Of course I know the formula to calculate them: how can I implement those formula in CFX-Post, in order to analyze them?

Thank you.
Kind regards,
MAttia.
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Old   April 3, 2009, 13:12
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Rikio
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Yes, define expressions from available variables to form variables you want. Define a quantitative that include the expression first, and then a variable.
Enjoy your work!
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Old   April 3, 2009, 14:42
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Mattia
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Yes, I got that.

But my problem is: how do I define those expressions?!

Let's say I have 2 variables x and y and I want to calculate z=2*x+y: where do I write that formula?! Probably you are saying in the quantitative window: OK, but how?! I try to add something new, but I couldn't.

Thank you.

Kind regards.
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Old   April 5, 2009, 04:21
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For your example, just give a name for a quantitative, coorZ, for example. Then define the quan as 2*x+y. It is so simple. Then define a variable as cZ, select the quantity coorZ as the expression. Just give different names for the quantitative and variable. Or there will be conflicts of name convention.
I think you did not have a good look at the documentation, right? Do this to fix your puzzle, it will help you much. ^_^
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Old   April 6, 2009, 05:36
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Mattia
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Well, I had read the manual, but with your answer it was easier to understand.

Thanks a bunch!

Cheers,
M.
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