Non-contact acoustic tests based on nanosecond laser ablation: Generation of a pulse sound source with a small amplitude

Naoki Hosoya, Itsuro Kajiwara, Tatsuo Inoue, Koh Umenai

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

A method to generate a pulse sound source for acoustic tests based on nanosecond laser ablation with a plasma plume is discussed. Irradiating a solid surface with a laser beam expands a high-temperature plasma plume composed of free electrons, ionized atoms, etc. at a high velocity throughout ambient air. The shockwave generated by the plasma plume becomes the pulse sound source. A laser ablation sound source has two features. Because laser ablation is induced when the laser fluence reaches 1012-1014 W/m2, which is less than that for laser-induced breakdown (1015 W/m2), laser ablation can generate a lower sound pressure, and the sound source has a hemispherical radiation pattern on the surface where laser ablation is generated. Additionally, another feature is that laser-induced breakdown sound sources can fluctuate, whereas laser ablation sound sources do not because laser ablation is produced at a laser beam-irradiation point. We validate this laser ablation method for acoustic tests by comparing the measured and theoretical resonant frequencies of an impedance tube.

Original languageEnglish
Pages (from-to)4254-4264
Number of pages11
JournalJournal of Sound and Vibration
Volume333
Issue number18
DOIs
Publication statusPublished - 2014 Sep 1

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ASJC Scopus subject areas

  • Acoustics and Ultrasonics
  • Condensed Matter Physics
  • Mechanical Engineering
  • Mechanics of Materials

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