Energy is extracted from a free stream fluid flow of wind or water by {HEAD ~ means} of {TAIL ~ a multi turn helicoid structure} with a relatively small pitch angle 
of
Energy is extracted from a free stream fluid flow of wind or water by { HEAD ~ means } of { TAIL ~ a multi turn helicoid structure } with a relatively small pitch angle
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH