CFD Online Discussion Forums

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   CFX (https://www.cfd-online.com/Forums/cfx/)
-   -   defining new expressions (https://www.cfd-online.com/Forums/cfx/63294-defining-new-expressions.html)

iperten April 3, 2009 11:07

defining new expressions
 
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.

rikio April 3, 2009 13:12

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!

iperten April 3, 2009 14:42

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.

rikio April 5, 2009 04:21

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. ^_^

iperten April 6, 2009 05:36

Well, I had read the manual, but with your answer it was easier to understand. ;)

Thanks a bunch!

Cheers,
M.


All times are GMT -4. The time now is 03:52.