Ultrasonic velocity measurements in liquids with high resolution—techniques, selected applications and perspectives

This review gives a short introduction into the principles of sound velocity measurements. The fundamentals of acoustical methods using continuous waves, pulse modulated signals and sharp pulses are summarized. Methods employing optical wave interactions with continuous ultrasonic waves are also described briefly. Recent advances in the different methods are presented, and the technical status of the currently preferred techniques is discussed in view of their merits and limitations, too. Particular emphasis is given to the sensitivity and accuracy of the methods. Selected examples of measurement applications indicate the extended usability spectrum in basic research as well as in materials' characterization, manufacturing processes and control routines.