USER_GETVAR, Time Derivate operation on vector

August 2, 2007, 06:19

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

August 2, 2007, 09:04

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

August 3, 2007, 05:49

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

Hello,

Has anyone found the Time Derivative expression?

I don´t find it and support help told me it doesn´t exist.

I really don´t know how to calculate the acceleration of fluid as the derivative of the Water.Velocity expression ?¿?¿

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!

August 2, 2007, 06:19	USER_GETVAR, Time Derivate operation on vector	#1
Nicolas Guest Posts: n/a	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

August 2, 2007, 09:04	Re: USER_GETVAR, Time Derivate operation on vector	#2
opaque Guest Posts: n/a	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

August 3, 2007, 05:49	Re: USER_GETVAR, Time Derivate operation on vector	#3
Nicolas Guest Posts: n/a	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...

June 18, 2010, 06:25	Searching for the Time Derivative file	#4
mar New Member María del Mar RF Join Date: Jun 2010 Posts: 3 Rep Power: 15	Hello, Has anyone found the Time Derivative expression? I don´t find it and support help told me it doesn´t exist. I really don´t know how to calculate the acceleration of fluid as the derivative of the Water.Velocity expression ?¿?¿ Any ideas? Kind regards.

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June 18, 2010, 06:37		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	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!