摘要
通过流场-声场同步测试实验,观测自由液面处双悬停气泡几近同时破裂,引起液面波动的瞬态流动行为与声学特性。利用短时傅里叶变换提取了声音信号的时-频谱图,同步分析了气泡破裂过程图像和声压图谱。结果表明,双悬停气泡相继破裂,气泡Ⅰ射流形成和气泡Ⅱ体积急剧收缩的时刻重叠,存在高于单气泡破裂0.5 Pa的声压激增现象,该声压峰值均大于单气泡破裂、体积急剧收缩、射流引起的声压幅值。双悬停气泡破裂引起的液面波动相向传播重叠时刻,也存在明显的声压峰值。其中,气泡Ⅰ射流形成和气泡Ⅱ体积急剧收缩重叠时刻的声信号中心频率约为1078 Hz;双悬停气泡破裂引起的液面振动波叠加时刻具有两个频域峰值,中心频率分别为1242 Hz和2063 Hz。
The transient flow behavior and acoustic characteristics of the liquid level fluctuation caused by the near-simultaneous rupture of double hovering bubbles at the free liquid surface were observed by simultaneous flow field-acoustic tests.The time-frequency spectrum of acoustic signal is extracted by short-time Fourier transform(STFT),and the bubble burst process image and sound pressure spectrum diagram are analyzed simultaneously.The results show that the double hovering bubbles burst one after another,the moment of bubbleⅠjet formation overlaps with the rapid contraction of bubbleⅡvolume,and the phenomenon of sound pressure surge is 0.5 Pa higher than that of single bubble burst.The peak values of sound pressure are all larger than the amplitude of sound pressure caused by the rapid volume shrinkage and the jet formation of the single bubble liquid surface rupture.The peak value of sound pressure also exists when the liquid level fluctuation caused by the double hovering bubble burst propagates in the opposite direction and overlaps.The acoustic signal center frequency at the moment of bubbleⅠjet formation and sharp shrinkage of bubbleⅡvolume overlap is 1078 Hz.The superposition time of the liquid surface vibration wave caused by the double-hovering bubble burst has two frequency domain peaks,the center frequencies are 1242 Hz and 2063 Hz,respectively.
作者
丛山昊
刘竞婷
王贵超
孙逊
陈颂英
CONG Shanhao;LIU Jingting;WANG Guichao;SUN Xun;CHEN Songying(School of Mechanical Engineering,Shandong University,Jinan 250061,Shandong,China;Key Laboratory of High Efficiency and Clean Mechanical Manufacture,Ministry of Education,Shandong University,Jinan 250061,Shandong,China)
出处
《化工学报》
EI
CAS
CSCD
北大核心
2021年第10期5123-5131,共9页
CIESC Journal
基金
国家自然科学青年基金项目(52006126,51906125)
山东省自然科学基金青年项目(ZR2020QE193)。
关键词
气泡
气泡破裂
液面波动
声压脉动叠加
短时傅里叶变换
时频谱图
bubble
bubble burst
liquid surface fluctuates
sound pressure pulsation superposition
short-time Fourier transform
time-frequency spectrum
