Said pressure drop in {TAIL ~ the fan duct exhaust side} creates in turn an increase in the intake air mass velocity, and an ideal increase in fan rotational velocity, as the volume in {HEAD ~ the exhaust side} of the duct is configurable, and thus can be ideally matched to any intake air mass volume according to the speed of the wind at any given time 
Said pressure drop in { TAIL ~ the fan duct exhaust side } creates in turn an increase in the intake air mass velocity , and an ideal increase in fan rotational velocity , as the volume in { HEAD ~ the exhaust side } of the duct is configurable , and thus can be ideally matched to any intake air mass volume according to the speed of the wind at any given time
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH