IMPACT OF BUBBLES ON UNDERWATER ACOUSTIC COMMUNICATION

Abstract

We often observe acoustic communication performance degradation when a ship traverses a communication link. As ships generate bubbles, we believe that these bubbles contribute largely to the observed performance degradation. However, the actual impact and its duration is not fully understood. In this thesis, we identify that the rapid channel variations are more long-lasting as compared to the strong attenuation, as the variations are caused by long-lived bubbles that are suspended in the ocean. The lifetime of these bubbles can be as long as a few hours. The impact of these bubbles is far-reaching as they have the potential to be advected by currents to distant locations. We quantify the impact of these bubbles. We also provide a physical explanation of the longevity of these bubbles. The characterization can be used as a representation of a class of channels where bubble advections from distant intermittent injections are known to exist.