中文摘要：

被动声源成像方法近年来越来越成为研究气泡声源的有效手段之一。本文所阐述的气泡声源成像方法,不仅能从有限数量的水听器测量信号中对气泡声源进行高分辨率的空间定位,还能重构出气泡声源的平均功率分布情况。为此,本文首先需要建立一个合适的气泡声源模型、进一步简化气泡声源在空间传播的多径效应,以便充分利用阵列信号处理的优势;然后,本文简要介绍基于波束形成、最小方差无失真响应和子空间分解等信号处理技术的气泡声源成像方法;并针对研究的射流气泡特点、流速和喷管性状等条件,还讨论了有限数量的水听器阵列对声源成像结果的影响。最后,本文通过仿真模拟说明了被动声源成像方法可以揭示气泡声源在气泡形成、生长和脱离喷管等阶段的声源平均功率高分辨率空间分布情况。该方法能够有效“看见”气泡声源、弥补了高超速相机拍摄气泡图像的不足。

英文摘要：

Nowadays passive acoustic imaging has become one of the most effective methods in studying the sound emission of jet bubbles at low airflow rates. This paper presents a proof of concept that our proposed approach based on spatial filtering techniques can not only localize bubble acoustics, but also reconstruct acoustic power by only using the limited measurements at hydrophone array. First of all, an appropriate acoustic model of jet bubbles should be investigated carefully, and the acoustic propagation should be simplified appropriately in order to fit for array signal processing. Then the state-of-the-art spatial filters such as Beamforming, Capon and Music methods are extended for bubble acoustic imaging. And the deployment of hydrophone array is discussed according to the conditions of jet bubbles, airflow rates and sparged tank. Finally acoustic imaging results from simulations can show vividly acoustic power distributions with high spatial resolution and moderate dynamics during the jet bubble formation, detachment and vibration. Base on this proof of concept, limited number of hydrophone array can be effectively used in underwater experiments. Moreover our proposed approach allows to visualize the bubble sound distribution with respect to bubble images from high speed camera.