Hi All,
Those are quite interesting videos! That vortex generator just drives the air into the floor dramatically. You know they gotta be generating allot of drag to do that.
The issue with such techniques is tuning them to get the air to just deflect lightly, and curve away from the roadway and go parallel with it. Rather than as was seen in the video. And do that with a minimum of vortex generator. Otherwise the drag reduced by eliminating the tail tumble of the air, will just be overcome by the drag of the vortex generator.
Streamlining is a much more reliable method for those without the windtunel and force gauges needed to tune up vortex generators to the specific vehicle application.
I found some downloads on that web page. In his own report from 2004 he reports no VG's resulted in less drage (40 degree boattail).
http://www.vortaflow.com/consulting/...unt%20body.pdf
And that he was going to investigate smaller VG's.