Noise Generation of Air Bubbles in Water: An Experimental Study of Creation and Splitting

Although the study of two-phase flow, especially air-water mixtures, has received much attention in recent years, little has been done concerning the noise' generated by non-cavitating air water flows. The main purpose of this work is to examine these flows; in particular, to look at the noise associated with the creation of air bubbles at a nozzle, and the noise radiated by air bubbles splitting in the shear layer of a submerged turbulent water jet. Experiments were conducted to measure the sound pressure levels associated with bubble creation and bubble splitting, under a variety of conditions. Comparison were made with existing theories. An improved physical understanding of the mechanism of noise generation was gained through data analysis and photographic studies. Recommendations for further research are given.