Swirl specification for actuator disc
 

Hi
I am simulating a propeller powered aircraft and am representing the propeller as an actuator disc. I am using the fan boundary condition to implement the actuator disc.
I have calculated the delta pressure across the disc from Froude's momentum theory and will specify the pressure jump across the fan surface as a constant with this value.

I know the RPM of my propeller as well and want to include the tangential velocity due to it. I know that this will be done by the 'swirl' definition.

Question: How do I actually define this in Fluent as a boundary condition? Will I need to create a UDF to calculate rps*radial location for the local tangential velocity or is it enough if I just enter a constant with the entire propeller radius for tangential velocity?

Based on the Fluent manual (i have attached the equation), I can also insert a polynomial expression where the coefficient of r^1 is the RPS of my fan, and all other cooefficients are zero?
So, the expression I input would be
" 0 0 RPS"

I guess this is a correct approach?