Speed-of-Sound Measurements in Liquids Using Time-of-Flight Sensors

Speed of Sound Variation
Example for the apparent speed-of-sound variation with time probably due to deposition of small bubbles at the transducer and reflector faces. Cleaning of the faces (green marks) resets sensor output to a well reproducible value (blue line).

by Christoph von Rohden

Potentials and limitations of commercial sensors for in-situ speed-of-sound measurements in liquids working with the time-of-flight principle are discussed on the basis of laboratory investigations and an extended sensor calibration in pure water.