Impact and Departure Dynamics of Droplets and Bubbles
Droplets and bubbles are important for understanding natural phenomena such as falling raindrops, airborne disease transmission, and plant respiration systems, and also for engineering contexts such as semiconductor fabrication, nuclear power plants, and electronics cooling. However, still, more und...
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Virginia Tech
2022
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ftvirginiatec:oai:vtechworks.lib.vt.edu:10919/111211 2024-05-19T07:42:14+00:00 Impact and Departure Dynamics of Droplets and Bubbles Park, Hyunggon Engineering Science and Mechanics Boreyko, Jonathan B. Ragab, Saad A. Jung, Sunghwan Schmale, David G. III Socha, John J. 2022-07-11 ETD application/pdf http://hdl.handle.net/10919/111211 en eng Virginia Tech vt_gsexam:35163 http://hdl.handle.net/10919/111211 In Copyright http://rightsstatements.org/vocab/InC/1.0/ Droplets Bubbles Impact Departure Dissertation 2022 ftvirginiatec 2024-04-24T00:53:27Z Droplets and bubbles are important for understanding natural phenomena such as falling raindrops, airborne disease transmission, and plant respiration systems, and also for engineering contexts such as semiconductor fabrication, nuclear power plants, and electronics cooling. However, still, more understanding is needed of these complex dynamics problems. This dissertation will talk about the droplet impact and bubble departure dynamics that are happening on various surfaces. In Chapters 2 and 3, we will explore how raindrops can transmit plant pathogens. When the raindrop impacts the infected wheat leaf, the micron-sized dry spore can liberate from the surface in two different ways: dry dispersal and wet dispersal. The dry spore can liberate from the surface by the inertia of the drop, after that, the air vortex generated by the drop impact can carry the dry spores above the laminar boundary layer, with the potential for long-distance transport. For the wet dispersal, spore-laden droplets can be generated after raindrop impact, but how these spore-laden droplets can make neighboring plant diseases is still a mystery. We have shown that the splashed droplets can stick to the adjacent healthy leaf depending on the inertia of the impacting droplet, anisotropic leaf orientation, and whether it is treated with fungicide or not. In Chapter 4, We design a micropillar aluminum substrate that preferentially grows frost on top of the pillars. When deposited droplets impact the frost-tipped pillars, the dynamic pressure causes the water to wick within the frost faster than it can impale the gaps between the pillars. Upon freezing, this safely suspends the resulting ice sheet in the air-trapping Cassie state, without any surface coatings required. For the last part (Chapter 5), we investigated the bubble coalescence dynamics that can depart the bubble with a micrometer size. We made the micro-structured surfaces tailored to nucleation sites to enable the coalescence-induced departure of micro-bubbles. A scaling model ... Doctoral or Postdoctoral Thesis Ice Sheet VTechWorks (VirginiaTech) |
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VTechWorks (VirginiaTech) |
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English |
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Droplets Bubbles Impact Departure |
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Droplets Bubbles Impact Departure Park, Hyunggon Impact and Departure Dynamics of Droplets and Bubbles |
topic_facet |
Droplets Bubbles Impact Departure |
description |
Droplets and bubbles are important for understanding natural phenomena such as falling raindrops, airborne disease transmission, and plant respiration systems, and also for engineering contexts such as semiconductor fabrication, nuclear power plants, and electronics cooling. However, still, more understanding is needed of these complex dynamics problems. This dissertation will talk about the droplet impact and bubble departure dynamics that are happening on various surfaces. In Chapters 2 and 3, we will explore how raindrops can transmit plant pathogens. When the raindrop impacts the infected wheat leaf, the micron-sized dry spore can liberate from the surface in two different ways: dry dispersal and wet dispersal. The dry spore can liberate from the surface by the inertia of the drop, after that, the air vortex generated by the drop impact can carry the dry spores above the laminar boundary layer, with the potential for long-distance transport. For the wet dispersal, spore-laden droplets can be generated after raindrop impact, but how these spore-laden droplets can make neighboring plant diseases is still a mystery. We have shown that the splashed droplets can stick to the adjacent healthy leaf depending on the inertia of the impacting droplet, anisotropic leaf orientation, and whether it is treated with fungicide or not. In Chapter 4, We design a micropillar aluminum substrate that preferentially grows frost on top of the pillars. When deposited droplets impact the frost-tipped pillars, the dynamic pressure causes the water to wick within the frost faster than it can impale the gaps between the pillars. Upon freezing, this safely suspends the resulting ice sheet in the air-trapping Cassie state, without any surface coatings required. For the last part (Chapter 5), we investigated the bubble coalescence dynamics that can depart the bubble with a micrometer size. We made the micro-structured surfaces tailored to nucleation sites to enable the coalescence-induced departure of micro-bubbles. A scaling model ... |
author2 |
Engineering Science and Mechanics Boreyko, Jonathan B. Ragab, Saad A. Jung, Sunghwan Schmale, David G. III Socha, John J. |
format |
Doctoral or Postdoctoral Thesis |
author |
Park, Hyunggon |
author_facet |
Park, Hyunggon |
author_sort |
Park, Hyunggon |
title |
Impact and Departure Dynamics of Droplets and Bubbles |
title_short |
Impact and Departure Dynamics of Droplets and Bubbles |
title_full |
Impact and Departure Dynamics of Droplets and Bubbles |
title_fullStr |
Impact and Departure Dynamics of Droplets and Bubbles |
title_full_unstemmed |
Impact and Departure Dynamics of Droplets and Bubbles |
title_sort |
impact and departure dynamics of droplets and bubbles |
publisher |
Virginia Tech |
publishDate |
2022 |
url |
http://hdl.handle.net/10919/111211 |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_relation |
vt_gsexam:35163 http://hdl.handle.net/10919/111211 |
op_rights |
In Copyright http://rightsstatements.org/vocab/InC/1.0/ |
_version_ |
1799481895324483584 |