Trailing helical vortex core spacing
 

Hi,

I was wondering if anyone would know about an estimate of the spacing of trailing vortex cores behind yawed cylinders in highly idealized circumstances based on the geometry of the flow obstruction and/or dimensionless groups.

Through observation, these attached trailing vortex cores have incredibly uniform spacing behind a simple cylinder inclined 45 degrees to flow. Is there a predictive to to describe the spacing of these guys?

It's a long shot, but, I would really appreciate any insight that you might have. It'd be great to hear anything, even if the flow / geometry is even remotely similar.

Thanks!