Hi Is it possible to use two UDFs consecutively in the same simulation? If possible, how? Thanks Mech

As long as the UDFs are affecting different things, like a DEFINE_PROFILE and a DEFINE_SOURCE, or defining different sources, like an x-moment source or y-moment source, they can be used simultaneously.

If you want to have two things affecting, say, x-momementum at the same time, your best bet is to merge the UDFs together.

Hope this helps, Tom

Tom Thank you for you response. I am working with microflow. First I simulate flow with noslip condition. After converging I impose slip boundary condition on it. Now I want to use uniform flow condition(not parabolic i.e. u(y)=constant)at inlet condtion for no slip boundary condition where I have to use define pofile. Then I have to impose slip condition using define profile. So I need two UDFs. In the same UDF it is not possible. If you have more idea about it please help me. Also For single devivative like du/dx I can use C_DUDX(c,t) but for higher derivative like momentum source term d2u/dy2,d2u/dxdy or d2v/dy2 which macro are to be used or how to write these terms in UDF. Have a nice time. Bye Mech

Hi, maybe the best way to do is use a switch law macro, U can find that in UDF Manual. For d2u/dy2 I think u must implemente a simple incremental ratio such as (delta(du/dx))/dx in your UDF. I hope it's helpfull

Regard

Adriano

Hi Adriano Where is switch law macro? Will you mention the section number of the manual? Also I tried for 2nd order derivative but it is unmanagable. If you know I request you to clarify. Thanks Mech