[Taozi]

Dear All,

I know in Fluent UDF velocity gradient can be accessed at any cell anytime by C_U_G(c, t), appears to me that Fluent has velocity gradient computed at every timestep and stored in memory so it is ready-to-use.

In OpenFOAM only the primitive variables (p, U, tracer, etc) are stored (am I right?) and when you want to access derived variables such as their derivatives, you have to first compute it by yourself, this saves memory but also cause some trouble when you need those variables explicitly.

So what's the best practice of solving this? Do I need to declare variables like "volVectorField velocityGradient(...)" before the time loop and update this variable at end of each loop, or there is a better way?

Thank you!