DEFINE_SDOF_PROPERTIES external moment
 

Hi all

I need to apply a new force / moment to my UDF file which describes the motion of an object: Mass matrix is defined and only zz rotation is allowed. This object is like a pendulum, doesn't rotate about it's CG.

Now I want to add a moment to the rotation point (defined in FLUENT dynamic mesh GUI, as CG). For that I want to apply the following macro: prop[SDOF_LOAD_M_Z],
but in this case my moment force changes with the rotation angle of the object, and FLUENT doesn't allow me to input the following function:
(-(mass*grav*L*sin(DT_THETA(dt)[2])*sin(DT_THETA(dt)[2])))-(-(mass*grav*L*cos(DT_THETA(dt)[2])*cos(DT_THETA(dt)[2])))

How can I add these force to DEFINE_SDOF_PROPERTIES ?

Thank you in advance