Swirl Number Calculation
 

Hey all,

I am studying a burner and want to calculate the swirl number as follows:

S=(∫(WUr^2 dr)/(R∫U^2 rdr)

My aim is to calculate it at different planes in a few axial positions and see swirl decay in the combustion chamber.

I guess this would be very easy to do by writing a user defined field function but I do not have a lot of experience with those.

Could someone help me on how to write this?