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