Bubble-acoustic emissions: a tool for metallurgical process feedback?

Bubbles are sparged into molten metals in several metallurgical processes. Audible and often very loud sounds are generated by the formation and volumetric vibration of bubbles. Anedoctal evidence from plant operators is that there is a relation between the perceived quality of these noises and the process performance. However, translating this concept to practice is challenging and should benefit from a deeper understanding of the physics of bubble sound emission.