Acoustic Bubble Spectrometer(ABS)
ABS (Acoustic bubble spectrometer) is a device that acoustically measures the bubble size distribution and void fraction in liquid using two hydrophones. Compared to optical methods, ABS is affordable and easy to use. While optical methods make it difficult to separate air bubbles and other solid particles directly, the acoustic technology underlying ABS is very sensitive to air bubbles and at the same time insensitive to solid particles, It is possible to distinguish between the two.
Number of bubbles per frequency
Transmit waveform and receive wave