12 Replies Latest reply on Aug 25, 2016 3:29 PM by Bill McEachern

    Kutta Joukowski theorem for flow over a rotating cylinder

    Theo Linders

      Hi,

       

      I try to simulate the flow over a rotating cylinder in order to prove the Magnus effect. The diameter is 1 meter, length is 5 m, velocity is 40 m/s, the cylinder turns 90 rpm and the density is 1.2 kg/m3 so just in normal air. I used a computational domain in 2D with a width of 10 cms so, 1/50th of the total length of the cylinder.

      Because i want to simulate the flow around the cilinder i don't use a rotating region but i define a real wall as a boundary condition with the velocity and rotational speed; I defined a local and global mesh (see files included).

      When i calculate the lift by hand (Kutta Joukowski theorem from Lift of a Rotating Cylinder from the NASA site) the results are a lift force of 3552  N but when I use flow simulation and multiply the calculated 0.485 N with 50 (the comp. domain was 1/50 of the exact size) I only get a lousy 24.3 N.

      So i guess i'm doing something totally wrong.

       

      can anyone help me?

       

      thx

      Theo