[S_Tanuj]

Hello all,
I want to give rolling motion to my system. For that, I vitally need to consider tangential force acting on any location in the system. How can I write UDF for that and add it as a source term in the momentum equation in FLUENT?

if possible please give an example.
Thanks in advance.

[AlexanderZ]

you may go to boundary conditions
select the air-solid boundary
momentum tab
as a wall motion select moving wall
and specify your motion as well as shear conditions

[S_Tanuj]

That's true thankyou Sir. But I want to give SHM with the maximum amplitude of 30 degrees. To do that I have to incorporate the effect of tangential force on the system and that needs to be done using UDF (T_{tangential} = angular acceleration * radius). That UDF will be added as a source term in momentum equation in the "cell zone boundary condition". So how to write code for that? I can define angular acceleration, but the main point is while defining "radius".

Can we define radius with the help of x and y positions with [ND_ND] (The system is 2-D)?

Do I need to use for loop in UDF in DEFINE_SOURCE MACRO because at each cell radius value will be different?

I tried doing with it but, could not find the difference, so I am a bit confused whether I am going in correct path or not.
Please see the image attached for reference.