As an example the second derivation of the velocity component u in respect to the x-coordinate axis should be calculated: 1.)Define two expressions in the “Expression” tab: •my ux = u.grad_x •my uxx = ux.grad_x 2.)Define two additional variables of scalar type: •ux [s^-1] •uxx [m^-1 s^-1] 3.)Assign the defined expressions as definitions of the additional variables in the “Fluid Models” tab of a domain. Therefor you have to choose the option “Algebraic Equation” to define the additional variables. •ux = my ux •uxx = my uxx For further information please have a look in attached PDF-document and CFX example file.

Attachments:
1. 2040475.zip
2. Definition_of_Second_Derivation_of_a_Variable_in_CFX_Pre.pdf