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-   -   Makcro for Velocity-derivatives (http://www.cfd-online.com/Forums/fluent/29683-makcro-velocity-derivatives.html)

Christian April 26, 2002 05:17

Makcro for Velocity-derivatives
 
Hi!

I am using Fluent 6.0 an want to access velocity-derivatives within a UDF. The macro in the manual

e.g. C_DWDY(c, t)

seems not to work. Has anybody come across this problem before? I have heard of a problem with these macros before but don"t remember the solution if there was any.

Thanks in advance, Christian

Johnix April 26, 2002 11:34

Re: Makcro for Velocity-derivatives
 
Hi,

I think it can work. I had used it before.

Maybe you can state your problem in details, then ...

It may not work if the case is 2-D (kidding).


Christian April 27, 2002 02:14

Re: Macro for Velocity-derivatives
 
Hi!

Nice joke.... I want to use the macro for the computation of a component of the wall stress tensor. The problem is 3d and Fluent computes the derivative, I can see this e.g. in the contour-plot. but the value seems not o be available for my UDF. I have read in tha manual that not all derivatives are accesibble until the solver memory is kept from beeing freed. there is a text command that should prevent this but I don't know how it should be used. But I think it only deals with the C_U_G(c, t) macros. But I need the partial derivative so I cannot work with these. Maybe anybody of you knows a solution,

thanks in advance, Christian


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