The apparatus 1 wherein the flow obstruction comprises a plurality of bluff bodies and the oscillating flow components are produced from {HEAD ~ vortices} shed from {TAIL ~ the bluff bodies} 
shed from
The apparatus 1 wherein the flow obstruction comprises a plurality of bluff bodies and the oscillating flow components are produced from { HEAD ~ vortices } shed from { TAIL ~ the bluff bodies }
OTH 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 REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL