The upstream volume 66 is in {HEAD ~ direct fluid communication} with {TAIL ~ the coolant inlet} 40, and the downstream volume 68 is in direct fluid communication with the coolant outlet 42 
with
The upstream volume 66 is in { HEAD ~ direct fluid communication } with { TAIL ~ the coolant inlet } 40 , and the downstream volume 68 is in direct fluid communication with the coolant outlet 42
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH