What is the S-coefficient in Magnus Effect?

1. Nov 4, 2013

smee

Hello,
I am studying Magnus Effect for the first time, I would like some help here, please.

The formula for Magnus effect as shown was:

[F][/m] = S (v × ω)

Where v = velocity of fluid,
ω = angular velocity,
S = air resistance coefficient across the surface of sphere.

How can I find the value of S? Is it fixed or does it need another formula?