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