{HEAD ~ The flow surface} includes {TAIL ~ a first portion} and a second portion extending downstream from the first portion 
{ HEAD ~ The flow surface } includes { TAIL ~ a first portion } and a second portion extending downstream from the first portion
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH