CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   Unit of Expression (http://www.cfd-online.com/Forums/cfx/20395-unit-expression.html)

Fing May 27, 2004 01:40

Unit of Expression
 
Hello,

I would like to input a viscosity expression but I can not how to solve the problem of the unit of the expression. My expression will be:

M_u = exp(1.2 - 2.9*log_e(4.5*sstrnr))

where M_u is dynamic viscosity, sstrnr is the strain rate. How can I solve the unit problem?

Thanks,

Fing

matej May 27, 2004 03:41

Re: Unit of Expression
 
What I allways do is simple trick. in logs and exps multiplying the variables with 1 of reciprocal unit, and multiplying the result with a 1.0 with the desired unit.

if you have a some variable A [m^2] in a exp(A), and you want the result B in [K] using formula B= 100.0*exp(A), (really silly example), what you do is: B=100.0 [K] * exp(A *1.0 [m^-2])

and that's it!

matej


Fing May 27, 2004 10:17

Thank you, matej
 
Thanks, matej.

Regards,

Fing


All times are GMT -4. The time now is 09:32.