I would consider using a scale-resolving turbulence model instead of the URANS approach. Try using the Stress-Blended Eddy Simulation (SBES) model. You might also include turbulence transition modeling. Of course, you'll need to have an appropriate mesh proximal to the cylinder with y+~=1 and 10-15 inflation layers in the boundary layer. Using this approach allows for reasonable prediction of the Strouhal number, so it should be appropriate for your FSI application.
You are navigating away from the AIS Discovery experience