Furthermore, the larger, and volume configurable duct volume behind the fan represents a volume into which {TAIL ~ the fixed intake aperture air volume} is fed, thus representing {HEAD ~ a diffusion} of the intake air mass, and a consequent pressure drop in the duct behind the turbine type fan 
Furthermore , the larger , and volume configurable duct volume behind the fan represents a volume into which { TAIL ~ the fixed intake aperture air volume } is fed , thus representing { HEAD ~ a diffusion } of the intake air mass , and a consequent pressure drop in the duct behind the turbine type fan
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH 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