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-   -   USER_GETVAR, Time Derivate operation on vector (http://www.cfd-online.com/Forums/cfx/24346-user_getvar-time-derivate-operation-vector.html)

Nicolas August 2, 2007 06:19

USER_GETVAR, Time Derivate operation on vector
 
Hello, I'm trying to extract the kinetic energy from my CFD domain during transient simulation using a USER FORTRAN routine. I want to create a new variable "time derivative of the velocity vector" with the function USER_GETVAR. ".Time Derivate" operator seems to work on scalar but not on vector. Is there anybody who encountered the same problem and found out a solution? Thanks

opaque August 2, 2007 09:04

Re: USER_GETVAR, Time Derivate operation on vector
 
Dear Nicolas,

What kind of error you get when calling USER_GETVAR with

MyFluidPhase.Velocity.Time Derivative ?

Then, we can try to help you.

Opaque


Nicolas August 3, 2007 05:49

Re: USER_GETVAR, Time Derivate operation on vector
 
Thanks for your help, I understood my mistake! I used the formula MyFluidPhase.Velocity.Time Derivate instead of MyFluidPhase.Velocity.Time Derivative. The confusion comes from the help file of CFX 11...

mar June 18, 2010 06:25

Searching for the Time Derivative file
 
Hello,

Has anyone found the Time Derivative expression?

I donīt find it and support help told me it doesnīt exist.

I really donīt know how to calculate the acceleration of fluid as the derivative of the Water.Velocity expression ?ŋ?ŋ

Any ideas?

Kind regards.

ghorrocks June 18, 2010 06:37

It does not exist. The previous posts in this thread are news to me - I don't think they work - but I would love to be shown to be wrong!


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