The spiral flow increases the rate of {TAIL ~ convection} and thus increases {HEAD ~ the cooling capacity} of the cooling system 
The spiral flow increases the rate of { TAIL ~ convection } and thus increases { HEAD ~ the cooling capacity } of the cooling system
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH