An impeller is mounted in {HEAD ~ the trailing end} of {TAIL ~ the concavity} and a stator trails the impeller 
of
An impeller is mounted in { HEAD ~ the trailing end } of { TAIL ~ the concavity } and a stator trails the impeller
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH