Wall shear stress from jetting cavitation bubbles: influence of the stand-off distance and liquid viscosity
We study systematically the cavitation-induced wall shear stress on rigid boundaries as a function of liquid viscosity and stand-off distance using axisymmetric volume of fluid (VoF) simulations. Here, is defined with the initial distance of bubble centre from the wall and the bubble equivalent radi...
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2022
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/163943 |
| _version_ | 1811683192497766400 |
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| author | Zeng, Qingyun An, Hongjie Ohl, Claus-Dieter |
| author2 | School of Physical and Mathematical Sciences |
| author_facet | School of Physical and Mathematical Sciences Zeng, Qingyun An, Hongjie Ohl, Claus-Dieter |
| author_sort | Zeng, Qingyun |
| collection | NTU |
| description | We study systematically the cavitation-induced wall shear stress on rigid boundaries as a function of liquid viscosity and stand-off distance using axisymmetric volume of fluid (VoF) simulations. Here, is defined with the initial distance of bubble centre from the wall and the bubble equivalent radius at its maximum expansion. The simulations predict accurately the overall bubble dynamics and the time-dependent liquid film thickness between the bubble and the wall prior to the collapse. The spatial and temporal wall shear stress is discussed in detail as a function of and the inverse Reynolds number. The amplitude of the wall shear stress is investigated over a large parameter space of viscosity and stand-off distance. The inward stress is caused by the shrinking bubble and its maximum value follows (kPa) for <![CDATA[$0.5<\gamma. The expanding bubble and jet spreading on the boundary produce an outward-directed stress. The maximum outward stress is generated shortly after impact of the jet during the early spreading. We find two scaling laws for the maximum outward stress with for and for, where is the jet impact velocity and is the distance between lower bubble interface and wall prior to impact. |
| first_indexed | 2024-10-01T04:08:50Z |
| format | Journal Article |
| id | ntu-10356/163943 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T04:08:50Z |
| publishDate | 2022 |
| record_format | dspace |
| spelling | ntu-10356/1639432022-12-22T08:58:43Z Wall shear stress from jetting cavitation bubbles: influence of the stand-off distance and liquid viscosity Zeng, Qingyun An, Hongjie Ohl, Claus-Dieter School of Physical and Mathematical Sciences Science::Physics Bubble Dynamics Cavitation We study systematically the cavitation-induced wall shear stress on rigid boundaries as a function of liquid viscosity and stand-off distance using axisymmetric volume of fluid (VoF) simulations. Here, is defined with the initial distance of bubble centre from the wall and the bubble equivalent radius at its maximum expansion. The simulations predict accurately the overall bubble dynamics and the time-dependent liquid film thickness between the bubble and the wall prior to the collapse. The spatial and temporal wall shear stress is discussed in detail as a function of and the inverse Reynolds number. The amplitude of the wall shear stress is investigated over a large parameter space of viscosity and stand-off distance. The inward stress is caused by the shrinking bubble and its maximum value follows (kPa) for <![CDATA[$0.5<\gamma. The expanding bubble and jet spreading on the boundary produce an outward-directed stress. The maximum outward stress is generated shortly after impact of the jet during the early spreading. We find two scaling laws for the maximum outward stress with for and for, where is the jet impact velocity and is the distance between lower bubble interface and wall prior to impact. H.A. acknowledges funding from an Australian Research Council Future Fellowship. This research was partly funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under grant OH 75/4-1. 2022-12-22T08:58:43Z 2022-12-22T08:58:43Z 2022 Journal Article Zeng, Q., An, H. & Ohl, C. (2022). Wall shear stress from jetting cavitation bubbles: influence of the stand-off distance and liquid viscosity. Journal of Fluid Mechanics, 932, A14-. https://dx.doi.org/10.1017/jfm.2021.997 0022-1120 https://hdl.handle.net/10356/163943 10.1017/jfm.2021.997 2-s2.0-85120815601 932 A14 en Journal of Fluid Mechanics © 2021 The Author(s). Published by Cambridge University Press. All rights reserved. |
| spellingShingle | Science::Physics Bubble Dynamics Cavitation Zeng, Qingyun An, Hongjie Ohl, Claus-Dieter Wall shear stress from jetting cavitation bubbles: influence of the stand-off distance and liquid viscosity |
| title | Wall shear stress from jetting cavitation bubbles: influence of the stand-off distance and liquid viscosity |
| title_full | Wall shear stress from jetting cavitation bubbles: influence of the stand-off distance and liquid viscosity |
| title_fullStr | Wall shear stress from jetting cavitation bubbles: influence of the stand-off distance and liquid viscosity |
| title_full_unstemmed | Wall shear stress from jetting cavitation bubbles: influence of the stand-off distance and liquid viscosity |
| title_short | Wall shear stress from jetting cavitation bubbles: influence of the stand-off distance and liquid viscosity |
| title_sort | wall shear stress from jetting cavitation bubbles influence of the stand off distance and liquid viscosity |
| topic | Science::Physics Bubble Dynamics Cavitation |
| url | https://hdl.handle.net/10356/163943 |
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