{HEAD ~ The cross section} of {TAIL ~ flow} of the tube 20 in this region is given a transition radius R, the size of which in principle depends on the flow inside the tube 20 
of
{ HEAD ~ The cross section } of { TAIL ~ flow } of the tube 20 in this region is given a transition radius R , the size of which in principle depends on the flow inside the tube 20
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL 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 OTH OTH OTH