衝撃波後方の高Weber数流れに誘起される単一液滴の微粒化

Breakup of single droplet induced by high weber number flow behind shock wave

朝原 誠*; 岩崎 航大*; 神谷 朋宏 ; 水野 恭兵*; 岩月 一馬*; 宮坂 武志*

Asahara, Makoto*; Iwasaki, Kodai*; Kamiya, Tomohiro; Mizuno, Kyohei*; Iwatsuki, Kazuma*; Miyasaka, Takeshi*

衝撃波後方の高速気流中における単一液滴の微粒化を高時空間分解能で撮影した。catastrophic breakup形態に該当する高Weber数条件において、液滴の上流側界面における波立ちの波長はKelvin-Helmholtz不安定性の臨界波長より大きい(波立ちの波長は安定領域に属する)が、Rayleigh-Taylor不安定性の理論波長とおおよそ一致した。したがって、上流側の界面の波立ちは、小さな擾乱がRayleigh-Taylor不安定性によって発達したことで形成されたと考えられる。また、フラグメントの拡散幅はWeber数に依存しないことが確認された。

Breakup of a single droplet induced by a high-velocity gas flow behind a shock wave was observed with high spatio-temporal accuracy imaging, and the behavior of fragment formation was observed. In the high Weber number region corresponding to catastrophic breakup, the wavelength of the upstream interfacial wave of the droplet was larger than the critical wavelength of the Kelvin-Helmholtz instability (wavelength in the stability region), which was roughly consistent with the theoretical wavelength of the Rayleigh-Taylor instability. Therefore, the upstream interfacial wave of the droplet is generated by the development of small disturbances due to the Rayleigh-Taylor instability. The measured fragment diffusion widths were found to be independent of the Weber number.