A vortex shedding flowmeter uses {HEAD ~ two ultrasonic transducers} to generate {TAIL ~ an acoustic beam} at a selected carrier frequency 
A vortex shedding flowmeter uses { HEAD ~ two ultrasonic transducers } to generate { TAIL ~ an acoustic beam } at a selected carrier frequency
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH