Jetting of viscous droplets from cavitation-induced Rayleigh-Taylor instability
Liquid jetting and fragmentation are important in many industrial and medical applications. Here, we study the jetting from the surface of single liquid droplets undergoing internal volume oscillations. This is accomplished by an explosively expanding and collapsing vapour bubble within the droplet....
| Main Authors: | , , , |
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| Format: | Journal Article |
| Language: | English |
| Published: |
2020
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| Online Access: | https://hdl.handle.net/10356/142585 |
| _version_ | 1824455133723885568 |
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| author | Zeng, Qingyun Gonzalez-Avila, Silvestre Roberto Voorde, Sophie Ten Ohl, Claus-Dieter |
| author2 | School of Physical and Mathematical Sciences |
| author_facet | School of Physical and Mathematical Sciences Zeng, Qingyun Gonzalez-Avila, Silvestre Roberto Voorde, Sophie Ten Ohl, Claus-Dieter |
| author_sort | Zeng, Qingyun |
| collection | NTU |
| description | Liquid jetting and fragmentation are important in many industrial and medical applications. Here, we study the jetting from the surface of single liquid droplets undergoing internal volume oscillations. This is accomplished by an explosively expanding and collapsing vapour bubble within the droplet. We observe jets emerging from the droplet surface, which pinch off into finer secondary droplets. The jetting is excited by the spherical Rayleigh-Taylor instability where the radial acceleration is due to the oscillation of an internal bubble. We study this jetting and the effect of fluid viscosity experimentally and numerically. Experiments are carried out by levitating the droplet in an acoustic trap and generating a laser-induced cavitation bubble near the centre of the droplet. On the simulation side, the volume of fluid method (OpenFOAM) solves the compressible Navier-Stokes equations while accounting for surface tension and viscosity. Both two-dimensional (2-D) axisymmetric and 3-D simulations are performed and show good agreement with each other and the experimental observation. While the axisymmetric simulation reveals how the bubble dynamics results destabilizes the interface, only the 3-D simulation computes the geometrically correct slender jets. Overall, experiments and simulations show good agreement for the bubble dynamics, the onset of disturbances and the rapid ejection of filaments after bubble collapse. Additionally, an analytic model for the droplet surface perturbation growth is developed based on the spherical Rayleigh-Taylor instability analysis, which allows us to evaluate the surface stability over a large parameter space. The analytic model predicts correctly the onset of jetting as a function of Reynolds number and normalized internal bubble energy. |
| first_indexed | 2025-02-19T03:33:22Z |
| format | Journal Article |
| id | ntu-10356/142585 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2025-02-19T03:33:22Z |
| publishDate | 2020 |
| record_format | dspace |
| spelling | ntu-10356/1425852020-06-25T01:42:34Z Jetting of viscous droplets from cavitation-induced Rayleigh-Taylor instability Zeng, Qingyun Gonzalez-Avila, Silvestre Roberto Voorde, Sophie Ten Ohl, Claus-Dieter School of Physical and Mathematical Sciences Science::Physics Bubble Dynamics Cavitation Liquid jetting and fragmentation are important in many industrial and medical applications. Here, we study the jetting from the surface of single liquid droplets undergoing internal volume oscillations. This is accomplished by an explosively expanding and collapsing vapour bubble within the droplet. We observe jets emerging from the droplet surface, which pinch off into finer secondary droplets. The jetting is excited by the spherical Rayleigh-Taylor instability where the radial acceleration is due to the oscillation of an internal bubble. We study this jetting and the effect of fluid viscosity experimentally and numerically. Experiments are carried out by levitating the droplet in an acoustic trap and generating a laser-induced cavitation bubble near the centre of the droplet. On the simulation side, the volume of fluid method (OpenFOAM) solves the compressible Navier-Stokes equations while accounting for surface tension and viscosity. Both two-dimensional (2-D) axisymmetric and 3-D simulations are performed and show good agreement with each other and the experimental observation. While the axisymmetric simulation reveals how the bubble dynamics results destabilizes the interface, only the 3-D simulation computes the geometrically correct slender jets. Overall, experiments and simulations show good agreement for the bubble dynamics, the onset of disturbances and the rapid ejection of filaments after bubble collapse. Additionally, an analytic model for the droplet surface perturbation growth is developed based on the spherical Rayleigh-Taylor instability analysis, which allows us to evaluate the surface stability over a large parameter space. The analytic model predicts correctly the onset of jetting as a function of Reynolds number and normalized internal bubble energy. 2020-06-25T01:42:34Z 2020-06-25T01:42:34Z 2018 Journal Article Zeng, Q., Gonzalez-Avila, S. R., Voorde, S. T., & Ohl, C.-D. (2018). Jetting of viscous droplets from cavitation-induced Rayleigh-Taylor instability. Journal of Fluid Mechanics, 846, 916-943. doi:10.1017/jfm.2018.284 0022-1120 https://hdl.handle.net/10356/142585 10.1017/jfm.2018.284 2-s2.0-85047106550 846 916 943 en Journal of Fluid Mechanics © 2018 Cambridge University Press. All rights reserved. |
| spellingShingle | Science::Physics Bubble Dynamics Cavitation Zeng, Qingyun Gonzalez-Avila, Silvestre Roberto Voorde, Sophie Ten Ohl, Claus-Dieter Jetting of viscous droplets from cavitation-induced Rayleigh-Taylor instability |
| title | Jetting of viscous droplets from cavitation-induced Rayleigh-Taylor instability |
| title_full | Jetting of viscous droplets from cavitation-induced Rayleigh-Taylor instability |
| title_fullStr | Jetting of viscous droplets from cavitation-induced Rayleigh-Taylor instability |
| title_full_unstemmed | Jetting of viscous droplets from cavitation-induced Rayleigh-Taylor instability |
| title_short | Jetting of viscous droplets from cavitation-induced Rayleigh-Taylor instability |
| title_sort | jetting of viscous droplets from cavitation induced rayleigh taylor instability |
| topic | Science::Physics Bubble Dynamics Cavitation |
| url | https://hdl.handle.net/10356/142585 |
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