The cross section of {HEAD ~ flow} of {TAIL ~ 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
The cross section of { HEAD ~ flow } of { TAIL ~ 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
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL 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