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