{HEAD ~ The oscillating flow components} are detected with a pair of {TAIL ~ ultrasonic transducers} defining an acoustic path intersecting the vortices 
{ HEAD ~ The oscillating flow components } are detected with a pair of { TAIL ~ ultrasonic transducers } defining an acoustic path intersecting the vortices
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH