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plotting/monitoring maximum Mach number

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Old   June 24, 2012, 10:08
Default plotting/monitoring maximum Mach number
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Is there a way to plot/monitor the maximum Mach number during the course of a run?

(And not at a specific point, but for the entire fluid domain volume).

I'm getting a maximum Mach number message showing up in the output file, and I was just wondering if there's a way to plot/track/monitor that.

Help would be greatly appreciated.

Notes about the run:
It is a transient run. Timesteps are now 1e-7 [s]. Total time I think only works out to be for like 9e-3 [s] or something like that (although right now, it's not even getting past 2e-5 [s]), so I'm using the Mach number to try and help me debug the run.

Thanks.
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Old   June 24, 2012, 19:29
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Use a monitor point, set to max(Mach Number)@domain or something like that.
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Old   June 24, 2012, 21:55
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Quote:
Originally Posted by ghorrocks View Post
Use a monitor point, set to max(Mach Number)@domain or something like that.
If I got multiple domains, that would mean that I would have to use:

max(max(Mach Number)@domain1,max(Mach Number)@domain2,max(Mach Number)@domain3))?
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Old   June 25, 2012, 19:16
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Quote:
Originally Posted by ghorrocks View Post
Use a monitor point, set to max(Mach Number)@domain or something like that.
ERROR
The following unrecognised name was referenced: max.
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Old   June 25, 2012, 19:24
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Sorry, the command is maxVal()@domain. Look at the CFX Reference guide for full variable and function list
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Old   June 25, 2012, 19:37
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Sorry, the command is maxVal()@domain. Look at the CFX Reference guide for full variable and function list
Thanks. That's kind of interesting that they have different commands to get the maximum values.
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Old   June 25, 2012, 20:36
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Yes, it is confusing. But there is a bit of logic in there - the max() function returns the max of the arguement values, but maxVal looks at the mesh object referenced and returns the max value from that. The max function is a simple function equivalent to most languages, the maxVal function is known as a CFX callback (not sure why, they just are) function which works on mesh objects.
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Old   June 25, 2012, 20:40
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Quote:
Originally Posted by ghorrocks View Post
Yes, it is confusing. But there is a bit of logic in there - the max() function returns the max of the arguement values, but maxVal looks at the mesh object referenced and returns the max value from that. The max function is a simple function equivalent to most languages, the maxVal function is known as a CFX callback (not sure why, they just are) function which works on mesh objects.
Good to know.

So if I want to probe/query a parameter/value in the run, I would need to use maxVal, but if I want to find the maximum (between two things), I would use max().

Also it's interesting that it doesn't allow more than two arguments (so say...I have three domains, I can't ask it to compare and find the max values out of all three; I have to do them two at a time, and then find the max between the two pairs).

It would be nice if max() would be intelligent enough to be able to tell whether you're looking at a value, or as a comparison. But either way, it works. It takes a few more expressions to get there, but it works.
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