Atenuação do som, no meio submarino, usando a técnica de cortina de bolhas

Abstract

The earliest efforts in noise control were primarily aimed at minimizing sound emissions from air traffic and industrial activities, due to their harmful effects on workers and nearby communities. With the increasing human exploitation of the oceans, the need to mitigate excessive noise in the marine environment has become evident. Several studies have highlighted the adverse effects of continuous and high-intensity noise generated by individual sources such as vessels, construction activities, and offshore drilling operations. This type of noise interferes with communication, migration, foraging, reproduction, and other vital behaviors of marine organisms, ultimately affecting their survival and the overall balance of the underwater environment. One of the most widely studied and implemented mitigation techniques in other countries is the use of bubble curtains, which consist of creating an air barrier within the water column. This technique acts as an efficient acoustic reflection and absorption mechanism due to the difference in acoustic impedance and the natural resonance frequency of the bubbles, contributing to the attenuation of acoustic energy and consequently reducing the detrimental effects on marine life. Therefore, the present work aims to conduct a theoretical study on sound attenuation using the bubble curtain technique, as well as experiments in a controlled environment, specifically the acoustic tank of the Acoustical Engineering Laboratory at the Admiral Paulo Moreira Institute for Sea Studies (IEAPM), the experiments employ acoustic projectors operating in the frequency range from 400 Hz to 10 kHz. Such analysis will focus on the behavior of transmitted signals in both pulse and continuous-wave forms when interacting with the bubble curtain, contributing to the understanding of its effects and outcomes in underwater acoustic propagation.