the effect shaft size has on vorticity
 

Hi Folks,

apologise if this is the wrong place to put my question but I would be grateful if some of you could lend me your expertise.

I have currently trying to design a central shaft for a vertical axis tidal turbine, I am happy with the calculations for deflection and stress etc. however what I am not able to evaluate is the effect my chosen shaft diameter will have on the downstream blades via vorticity.

I am aware that the larger my shaft the larger my Reynolds number will be and this has a direct relationship with turbulence, I have also come across that the Strouhal number has a big contribution to play here and the critical St of 0.21

the approach I am considering using is takingthe maximum design RPM of the turbine converting to Hertz and using it as my oscillation frequency in the Strouhal equation and playing around with the d value? or is this ludicrous

if anyone has an experience in this analysis please share.

Thanks in advance,
Dave