Reply To: How to get shear rate macro in UDF?

[montenegro]

Hello.

Thank you for the reply.
I asked the question because I've seen some discussions where it is told that the C_STRAIN_RATE(c,t) macro is the shear rate and other where it is said that it is indeed the strain rate. I also read in the Fluent User's Guide that the strain rate is the shear rate.
However, I ran my calculations (with C_STRAIN_RATE(c,t) macro in my viscosity equation) and checked if the results made sense. The value of the shear rate should be zero all over a centerline in my channel and it is not when I pull the results for the "Strain Rate" in the "Derivatives" top down menu. The "dX-velocity/dy" is, though, hence my confusion.
Moreover, I used the C_DUDY(c,t) macro in my UDF (needed to use abs(C_DUDY(c,t)), because Fluent returns it with negative values in the lower side of my channel) and I could not achieve convergence.

Can you tell if there is something wrong with my procedure?

Thank you Best regards.