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Old   September 25, 2007, 12:03
Default CEL Expressions
  #1
Nick
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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??
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Old   September 25, 2007, 12:35
Default Re: CEL Expressions
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CycLone
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Try using "Absolute Pressure" instead of 'p', which is the relative pressure.
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Old   September 25, 2007, 12:57
Default Re: CEL Expressions
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Nick
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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.
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Old   September 25, 2007, 14:54
Default Re: CEL Expressions
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CycLone
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It should work. I would follow up the Post problem separately with support.
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