It should be appreciated that {HEAD ~ the heated air} in {TAIL ~ the plenum chamber} 28 passes though the inner perforated wall 32 in the general direction of arrow 42  
in
It should be appreciated that { HEAD ~ the heated air } in { TAIL ~ the plenum chamber } 28 passes though the inner perforated wall 32 in the general direction of arrow 42
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