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-   -   units of geometrical parameters lost (http://www.cfd-online.com/Forums/ansys-meshing/83115-units-geometrical-parameters-lost.html)

SoobY December 15, 2010 04:53

units of geometrical parameters lost
 
hi,

i think this is a rather common problem but i couldnt find a solution yet. I would like to make a thermal analysis where i have to vary a couple of parameters. the result should be the specific thermal resistance of my geometry. therefore, i need to multiply and add a couple of parameters in my parameter set in Ansys workbench.


p r o b l e m:

if I click the small box in the design modeler to make a dimension to be a parameter, the units are not transfered to the parameter set. however, the units of parameters in my steady-state thermal block are transfered to my parameter set. then, if i add or substract parameters in the parameter set using parameters from both blocks, it happens that the units are incorrect although the formula actually is correct. ansys states "Invalid operation:
1316 [kg^-1 m^-2 s^3 C] + 0.0005555 [kg^-1 s^3 C]"

is there some way to exclude the units like in MATLAB or what can i do to enable the units of my design modeler?

thanks a lot for your help

PSYMN December 20, 2010 17:23

Work arounds
 
We will work on making the function editor more tolerant of addins that don't include parameters.

In the mean time, here are 2 possible work arounds...

If you are using R13, you can insert an EXCEL system on the desk top. This system could take in the parameters and do your function without worrying about the units... it would produce an output parameter as your result which you could then optimize by.

You could also add units to your function... for instance, if X is a length parameter that should have been in mm, you could do the expression as:
Y = (5 mm) + (X * (1 mm))

SoobY January 10, 2011 04:58

thanks for your advice. I was wondering how to add units to my function. so i had to do it using excel.


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