partial derivative

January 17, 2006, 13:12

I want to define the Richardson number as an own expression. But therefore I need the partial derivative of the temperature dT/dx (read as partial) and of the velocity du/dx. How can I define it? I have only found examples with UserFortran and the calculation of the gradient. Do I also have to use UserFortran but how does it have to look like?

Regards

Rita

January 20, 2006, 11:12

Rita,

UserFortran is the only way to get your spacial derivatives. If you look in the back end of the Solver Modeling manual, you will see several examples on calculating the gradients of variables in User Fortran. It's pretty straight forward to take these and modify them for your use. The actual files are located in the examples directory on you installation path as well.

Jeff

Jimmyhanchn · May 21, 2018, 03:27

Quote:

Originally Posted by Jeff
;74621

Rita,

UserFortran is the only way to get your spacial derivatives. If you look in the back end of the Solver Modeling manual, you will see several examples on calculating the gradients of variables in User Fortran. It's pretty straight forward to take these and modify them for your use. The actual files are located in the examples directory on you installation path as well.

Jeff

Do you mean that it is impossible to input partial derivative in CEL function?

ghorrocks · May 21, 2018, 07:24

These posts were done 12 years ago and CFX has a lot more functions for calculating gradients and similar things now. I recommend you read the CFX Reference Manual, the section on CEL variables and functions for an explanation of what is available.

January 17, 2006, 13:12	partial derivative	#1
Rita Guest Posts: n/a	I want to define the Richardson number as an own expression. But therefore I need the partial derivative of the temperature dT/dx (read as partial) and of the velocity du/dx. How can I define it? I have only found examples with UserFortran and the calculation of the gradient. Do I also have to use UserFortran but how does it have to look like? Regards Rita

January 20, 2006, 11:12	Re: partial derivative	#2
Jeff Guest Posts: n/a	Rita, UserFortran is the only way to get your spacial derivatives. If you look in the back end of the Solver Modeling manual, you will see several examples on calculating the gradients of variables in User Fortran. It's pretty straight forward to take these and modify them for your use. The actual files are located in the examples directory on you installation path as well. Jeff

May 21, 2018, 07:24		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	These posts were done 12 years ago and CFX has a lot more functions for calculating gradients and similar things now. I recommend you read the CFX Reference Manual, the section on CEL variables and functions for an explanation of what is available. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Derivative matrix	jollage	Main CFD Forum	0	September 21, 2011 19:16
can i get pressure derivative in UDF?	ruirui389	Fluent UDF and Scheme Programming	4	April 8, 2011 05:12
Obtaining substantial or partial derivative of vel	KRK	FLUENT	0	January 10, 2007 13:35
Partial Derivative on a unstructured grid	Alessandro	FLUENT	0	September 7, 2005 16:40
Arbitrary Matching & Partial Boundaries	George	Siemens	6	July 10, 2001 10:58