Hello.

Is it possible to define an expression or AV equal to Pressure.Gradient (or Velocity.Gradient) in CFX pre and use it for some calculations??

Thomas

To add some precision, I would like to get: d2u/dx2 (second derivative of Velocity u). With USER_GETVAR, I can get without problem du/dx, as I get from this routine Velocity u.Gradient and all the composant (du/dx, du/dy, du/dz). As these composant are only available in CFX-Post, I cannot use them to calculate d2u/dx2. I can just calculate Velocity u.Gradient.Gradient... which is not the same!

Someone can help me?? Thomas

Nobody able to calculate d2u/dx2??

You cannot directly use gradients in CEL expressions; you'll have to write your own User Fortran routine to calculate the second derivative.

Yes but how?? Because I can get the second derivative, but not d2u/dx2...

Thomas, as Phil says you will have to implement a second derivative calculation in user fortran to get what you want. This is not available "built in".

Neale