Moving the vent location to either side of the vent {HEAD ~ follower} causes fluid or {TAIL ~ gas} to escape from one or the other cell 
causes
Moving the vent location to either side of the vent { HEAD ~ follower } causes fluid or { TAIL ~ gas } to escape from one or the other cell
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH