Perhaps is not exactly the right place to rise this up, but I hope I will be forgiven.
There is very little - if any - info about vertical axis turbines in a manner that is appropriate for demo or diy aim.
I noticed so far two main issues with vertical axis wind turbines:
a) the available voltage is going to be far less than one of a PV panel, at a similar phisical magnitude
Perhaps this comes from the PV being industrially manufactured while turbines have to be made from scratch in most dit cases => this leads me to the idea to use a "buffer" - like a super-capacitor and then periodically discharge it through the Joule thief circuit, but under higher voltage - that is something I never saw in the internet and I would be very glad to get your opinion
b) There is a dependence of the Joule circuit to the way the inductance is made or mounted. I have no idea how to approach this, except by trial and error - any tip or no-matter-how-personal opinion would be of great help.
For the time being I am working on the PV module, but I will finish very soon and start the fight with the electronic part of this wind turbine.
The plan is to use an (close to) exhausted 1.5 V AA Alkaline pile in place of the wind turbine while desk prototyping. Alternatively, I can mount a voltage divider to the NiMH 3 or 1 units that I already coupled to the PV generator.