Energy analysis on rebound dynamics of two droplets impacting a superhydrophobic surface simultaneously
When multiple droplets impact a superhydrophobic surface, coalescence between the droplets may lead to an increased viscous dissipation rate and thus an increased contact time. In this study, the impact of double droplets on a superhydrophobic surface is studied via a lattice Boltzmann model. The mo...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2021-05-01
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| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/5.0046690 |
| _version_ | 1818905818946338816 |
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| author | Xin Wang Yi-Bo Wang Li-Li Jiao Yan-Ru Yang Xiao-Dong Wang |
| author_facet | Xin Wang Yi-Bo Wang Li-Li Jiao Yan-Ru Yang Xiao-Dong Wang |
| author_sort | Xin Wang |
| collection | DOAJ |
| description | When multiple droplets impact a superhydrophobic surface, coalescence between the droplets may lead to an increased viscous dissipation rate and thus an increased contact time. In this study, the impact of double droplets on a superhydrophobic surface is studied via a lattice Boltzmann model. The morphology and contact time of the rebounding droplet are obtained for various droplet distances and Weber numbers. The simulations show that there are three kinds of rebound patterns, complete-coalescence rebound (CCR), partial-coalescence rebound (PCR), and no-coalescence rebound (NCR); and the contact time is the shortest in the PCR regime. An energy analysis is implemented to reveal the energy conversion mechanism. It is found that viscous dissipation strongly depends on the coalescence strength, and it increases monotonously from the CCR regime to the NCR regime. This result implies that the shortest contact time in the PCR regime does not arise from the reduced viscous dissipation but is attributed to the morphology of the rebounding droplet. Moreover, the simulations also show that the total kinetic energy at the rebound moment is the highest in the PCR regime; however, the restitution coefficient or the rebound velocity is lowest in this regime because a larger proportion of the total kinetic energy occurs in the transverse direction. Therefore, a shorter contact time does not imply a higher rebound velocity. |
| first_indexed | 2024-12-19T21:29:23Z |
| format | Article |
| id | doaj.art-33ccb4e7f6294ba0a23c6fa650037de2 |
| institution | Directory Open Access Journal |
| issn | 2158-3226 |
| language | English |
| last_indexed | 2024-12-19T21:29:23Z |
| publishDate | 2021-05-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj.art-33ccb4e7f6294ba0a23c6fa650037de22022-12-21T20:04:58ZengAIP Publishing LLCAIP Advances2158-32262021-05-01115055007055007-910.1063/5.0046690Energy analysis on rebound dynamics of two droplets impacting a superhydrophobic surface simultaneouslyXin Wang0Yi-Bo Wang1Li-Li Jiao2Yan-Ru Yang3Xiao-Dong Wang4State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, ChinaState Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, ChinaState Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, ChinaState Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, ChinaState Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, ChinaWhen multiple droplets impact a superhydrophobic surface, coalescence between the droplets may lead to an increased viscous dissipation rate and thus an increased contact time. In this study, the impact of double droplets on a superhydrophobic surface is studied via a lattice Boltzmann model. The morphology and contact time of the rebounding droplet are obtained for various droplet distances and Weber numbers. The simulations show that there are three kinds of rebound patterns, complete-coalescence rebound (CCR), partial-coalescence rebound (PCR), and no-coalescence rebound (NCR); and the contact time is the shortest in the PCR regime. An energy analysis is implemented to reveal the energy conversion mechanism. It is found that viscous dissipation strongly depends on the coalescence strength, and it increases monotonously from the CCR regime to the NCR regime. This result implies that the shortest contact time in the PCR regime does not arise from the reduced viscous dissipation but is attributed to the morphology of the rebounding droplet. Moreover, the simulations also show that the total kinetic energy at the rebound moment is the highest in the PCR regime; however, the restitution coefficient or the rebound velocity is lowest in this regime because a larger proportion of the total kinetic energy occurs in the transverse direction. Therefore, a shorter contact time does not imply a higher rebound velocity.http://dx.doi.org/10.1063/5.0046690 |
| spellingShingle | Xin Wang Yi-Bo Wang Li-Li Jiao Yan-Ru Yang Xiao-Dong Wang Energy analysis on rebound dynamics of two droplets impacting a superhydrophobic surface simultaneously AIP Advances |
| title | Energy analysis on rebound dynamics of two droplets impacting a superhydrophobic surface simultaneously |
| title_full | Energy analysis on rebound dynamics of two droplets impacting a superhydrophobic surface simultaneously |
| title_fullStr | Energy analysis on rebound dynamics of two droplets impacting a superhydrophobic surface simultaneously |
| title_full_unstemmed | Energy analysis on rebound dynamics of two droplets impacting a superhydrophobic surface simultaneously |
| title_short | Energy analysis on rebound dynamics of two droplets impacting a superhydrophobic surface simultaneously |
| title_sort | energy analysis on rebound dynamics of two droplets impacting a superhydrophobic surface simultaneously |
| url | http://dx.doi.org/10.1063/5.0046690 |
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