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-   -   Units inconsistency (CFX5.5) (http://www.cfd-online.com/Forums/cfx/18762-units-inconsistency-cfx5-5-a.html)

gilberto December 13, 2001 11:23

Units inconsistency (CFX5.5)
 
Hi, everyone,

I wanted to comment one problem, and see if you can help me with it.When I start CFX5.5, and I open my database, first thing I am getting is a window saying that I have a Radiation Units inconsistency.Why is that?I am not using any radiation. I do not know, but maybe this is part of the other problem I want to tell you.

I have some databases, with some drawings, and I set my geometry units to mm. When I solve the problem, is gives me the solution in m, although I know it should be mm (I've done some same runs in CFX5.4.1), so it gives me solutions, for instance in kg m^-1 s^-2 for pressure, and they are the same values I got in my other runs, in kg mm^-1 s^-2. This drives me a bit confused, so my question is:how can i change that,hoe can i make the program recognise that I do have mm in there and no meters,without having this silly inconsistency??

Well thanks for reading the whole message through, and hope you can help me,

Thanks,

Gilbert

Robin Steed December 13, 2001 11:54

Re: Units inconsistency (CFX5.5)
 
Hi Gilberto,

There are two unit selections in CFX-Build, one for the units your geometry is in, another for the units the solver will work with.

The geometry units are requested when you start a new database. However, both may be modified in CFX-Build by selecting "Preferences > Solution Units" or "Preferences > Geometry Units"

The default for solution units is SI.

Regards, Robin

gilberto December 13, 2001 12:15

Re: Units inconsistency (CFX5.5)
 
Hi, Robin,

Yes, I knew that, but what happens is I have fixed both to mm, and I am getting the results in m, but with the same value as if it was in mm.For instance, i Had some previous runs, and the values for velicity were from 0 to 3671 mm/s, that is 3.6 m/s. And we I ran this in CFX5.5, i got from 0 to 3671 m/s (exactly the same value).

And even in results files, already created .res files, from CFX5.4.1, it gives me the same numbers I was getting before, but in m, and that is quite strange.

Thanks,mate

Gilbert

Neale December 14, 2001 20:03

Re: Units inconsistency (CFX5.5)
 
I have a feeling that you are looking at your results in CFX-5.5 Post which does not currently account for solver solution units.

No need to worry though, solver has "solved" in your solution length units of "mm", output your results in solution units, and CFX-Post is actually working in your solution units. It's just that anytime that CFX-Post prints out a unit it only prints SI. Just ignore it for now and hopefully it should be fixed in the next patch update. In the meantime you might have to manually modify your images that you output so that they have the proper units displayed (eg, mm/s instead of m/s for velocity).

CFX-Visualise in CFX-5.4.1 did everything properly as far as solution units are concerned as it also should in CFX-5.5, so I think that might be the point of confusion. You can always use CFX-Visualise to post-process your results as well.

Neale.


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