CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   CEL Expressions (http://www.cfd-online.com/Forums/cfx/24591-cel-expressions.html)

Nick September 25, 2007 12:03

CEL Expressions
 
Hi, I'm trying to implement a CEL expression in CFX post, and for some reason the function won't plot properly. I checked to see the minimum pressure to see if there was some strange negative value somewhere, and the minimum came back as 787868 [Pa]

But when I try to apply the following expression

loge(p/(101325 [kg m^-1 s^-2]))

I get this error:

The problem was:

LOGe-OF-NON-POSITIVE

The error occurs on sub-expression: loge(p/(101325 [kg m^-1 s^-2]))

Any idea why this is happening??

CycLone September 25, 2007 12:35

Re: CEL Expressions
 
Try using "Absolute Pressure" instead of 'p', which is the relative pressure.

Nick September 25, 2007 12:57

Re: CEL Expressions
 
Unfortunately, I get the same result when I try using Absolute Pressure.

I don't really 'need' to see the plot, I just need to know that the function actually works so I can use it in a definition in CFX Pre. What I'm getting at, is that if I use the option in post to evaluate at a specific pressure, the function works just fine - No errors. It just fails when I try to plot it.

I guess what I'm asking is whether or not the function will work if I use it to define something in Pre.

CycLone September 25, 2007 14:54

Re: CEL Expressions
 
It should work. I would follow up the Post problem separately with support.


All times are GMT -4. The time now is 18:52.