FlygenKite

[PierreB]

@dougselsam

It’s easy to “say” a brim can produce five (5) times the power from the same turbine, but I remain in doubt of that figure.

Hi Doug,
A publication shows, in figure 6, a significant decrease of the power coefficient of a shrouded wind turbine, when wind speed increses, here from 2 m/s to 6 m/s:

https://www.researchgate.net/publication/350169818_Shrouded_wind_turbine_for_low_wind_speed

With my torus I also observed a decrease of efficiency when wind speed increased.

That said this decreasing is not observed for the specific shroud you refer (see figure 6):

A Shrouded Wind Turbine Generating High Output Power with Wind-lens Technology

@dougselsam

what do you think of my noting that the “brim” amounts to adding a “Gurney flap” to a shroud?

I saw the similarity (after you mentioned it), but I do not know the aerodynamic causes.