Because turbulence increases {TAIL ~ the rate} of convection, the turbulent action created by the protrusions in the first row increases the rate of convection of {HEAD ~ the cooling system} 
Because turbulence increases { TAIL ~ the rate } of convection , the turbulent action created by the protrusions in the first row increases the rate of convection of { HEAD ~ the cooling system }
OTH OTH OTH 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 HEAD HEAD HEAD HEAD HEAD HEAD HEAD