partial derivative
 

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

Re: partial derivative
 

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?

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.