Extended-resolution acoustic imaging of low-frequency wave sources by acoustic analogy-based tomography

Wangqiao Chen, Siyang Zhong, Xun Huang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)

Abstract

The weakest possible waves in nature are detectable by improving sensitive measurements, but the attainable imaging resolution of low-frequency waves is still challenging, especially in aeroacoustic experiments. In this work, we show how extended-resolution imaging of low-frequency wave sources can be achieved by incorporating acoustic analogy into tomography. First, an equivalent source of sound, which is dependent on the low-frequency target sound field, is produced due to the nonlinear coupling and interaction with an external high-frequency incident plane wave. Next, the low-frequency sources are reconstructed based on the induced sound waves recorded at the receivers. The induced sound waves are of high frequency to enable the extended-resolution imaging. The physical processes involved are theoretically explained based on the insightful acoustic analogy theory and the Born approximation. The numerical and experimental demonstration cases, with representative but straightforward configurations, show that the proposed method can identify the isolated target sources (at low frequencies) with a separation distance smaller than one-tenth to one-thirtieth of the wavelength, yielding much better resolution than the conventional acoustic imaging approaches. The results suggest that the proposed method will be a promising candidate to investigate the properties of an acoustic source within small regions, and, therefore, likely to be used in the study of the associated fluid physics.

Original languageEnglish
Article numberA12
JournalJournal of Fluid Mechanics
DOIs
Publication statusAccepted/In press - 2020
Externally publishedYes

Keywords

  • aeroacoustics
  • wave scattering

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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