{"id":{"repo_id":"baylor","oai_identifier":"oai:baylor-ir.tdl.org:2104/13779"},"canonical_url":"https://search.dev.ndltd.org/etd/baylor/oai:baylor-ir.tdl.org:2104/13779","repository":{"repo_id":"baylor","name":"Baylor University","base_url":"https://baylor-ir.tdl.org/server/oai/request"},"display":{"title":"High-fidelity simulation and data-driven modeling of drop aerobreakup.","abstract":"Aerobreakup of liquid drops is essential to various spray applications like fuel injection, drug delivery, spray painting, among others. Due to the highly transient nature and the wide range of spatial scales involved, experimental diagnostics is challenging and high-fidelity numerical simulation is an important alternative to improve the understanding of drop aerobreakup and improve atomizer design. Drop aerobreakup is controlled by multiple dimensionless parameters, including the Weber (We), Reynolds (Re), Ohnesorge (Oh) numbers and liquid-to-gas density ratio, among which, We is most commonly used to characterize different breakup regimes. The goal of this thesis is to characterize the aerobreakup of an isolated drop in a uniform gas stream through high fidelity interface-resolved simulation, and to develop physics-based and data-driven point-particle models for Lagrangian spray simulation. The sharp gas-liquid interface is resolved using a mass-momentum consistent VOF method. The open-source Basilisk solver has been used for the present simulations. The computaitonal domain is discretized using a quadtree/octree mesh to allow local refinement of mesh in user defined region. We have started from simulations of water drops at millimeter size and moderate We. The simulation results for drop shape evolution are validated against experiment and an excellent agreement has been achieved. When the drop is suddenly exposed to a uniform gas stream, the drop first deforms to a disk and then to an inflating bag with a peripheral rim. As the bag undergoes inflation, the liquid sheet thickness decreases over time rapidly. Rupture of the bag is initiated through hole nucleation which gradually expands and gets collected into a rim which surrounds the hole. This rim undergoes destabilization thus forming child drops. The high level details of the flow inside the drop has provided crucial insight to improve models to predict the drop shape evolution. The validated simulation approach is then extended to study the sub-millimeter drops. While drop size decreases, the value of Re and Oh decreases if We is kept constant. The purpose is then to investigate the additional effect of Re on drop deformation and critical We. Since the Rayleigh-Taylor instability (RTI) plays a critical role in the drop deformation and bag formation, when the aerodynamic drag coefficient changes with Re, the resulting acceleration and stability of the interface will change as well. Therefore it is important to thoroughly characterize the relation between the drag and the deformation of the drop over time.","abstract_html":"Aerobreakup of liquid drops is essential to various spray applications like fuel injection, drug delivery, spray painting, among others. Due to the highly transient nature and the wide range of spatial scales involved, experimental diagnostics is challenging and high-fidelity numerical simulation is an important alternative to improve the understanding of drop aerobreakup and improve atomizer design. Drop aerobreakup is controlled by multiple dimensionless parameters, including the Weber (We), Reynolds (Re), Ohnesorge (Oh) numbers and liquid-to-gas density ratio, among which, We is most commonly used to characterize different breakup regimes. The goal of this thesis is to characterize the aerobreakup of an isolated drop in a uniform gas stream through high fidelity interface-resolved simulation, and to develop physics-based and data-driven point-particle models for Lagrangian spray simulation. The sharp gas-liquid interface is resolved using a mass-momentum consistent VOF method. The open-source Basilisk solver has been used for the present simulations. The computaitonal domain is discretized using a quadtree/octree mesh to allow local refinement of mesh in user defined region. We have started from simulations of water drops at millimeter size and moderate We. The simulation results for drop shape evolution are validated against experiment and an excellent agreement has been achieved. When the drop is suddenly exposed to a uniform gas stream, the drop first deforms to a disk and then to an inflating bag with a peripheral rim. As the bag undergoes inflation, the liquid sheet thickness decreases over time rapidly. Rupture of the bag is initiated through hole nucleation which gradually expands and gets collected into a rim which surrounds the hole. This rim undergoes destabilization thus forming child drops. The high level details of the flow inside the drop has provided crucial insight to improve models to predict the drop shape evolution. The validated simulation approach is then extended to study the sub-millimeter drops. While drop size decreases, the value of Re and Oh decreases if We is kept constant. The purpose is then to investigate the additional effect of Re on drop deformation and critical We. Since the Rayleigh-Taylor instability (RTI) plays a critical role in the drop deformation and bag formation, when the aerodynamic drag coefficient changes with Re, the resulting acceleration and stability of the interface will change as well. Therefore it is important to thoroughly characterize the relation between the drag and the deformation of the drop over time.","abstract_has_math":false,"creators":["Mahmood, Taofiq Hasan, 1992-"],"institution":"Baylor University.","degree_name":"Ph.D.","degree_level":"Doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Ling, Stanley (Yue)"],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-05","date_published":"2025-05","updated_at":"2026-07-24T01:08:16Z","subjects":["Aerobreakup.","DNS.","Data-driven modeling."],"languages":["en"],"rights":["Baylor University works are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. Contact libraryquestions@baylor.edu for inquiries about permission."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2104/13779","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Ling, Stanley (Yue)"]},{"key":"dc:creator","label":"Author","values":["Mahmood, Taofiq Hasan, 1992-"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-09-05T17:22:47Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-05"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Baylor University."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Aerobreakup.","DNS.","Data-driven modeling."]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Baylor University works are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. Contact libraryquestions@baylor.edu for inquiries about permission."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/2104/13779"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Aerobreakup of liquid drops is essential to various spray applications like fuel injection, drug delivery, spray painting, among others. Due to the highly transient nature and the wide range of spatial scales involved, experimental diagnostics is challenging and high-fidelity numerical simulation is an important alternative to improve the understanding of drop aerobreakup and improve atomizer design. Drop aerobreakup is controlled by multiple dimensionless parameters, including the Weber (We), Reynolds (Re), Ohnesorge (Oh) numbers and liquid-to-gas density ratio, among which, We is most commonly used to characterize different breakup regimes. The goal of this thesis is to characterize the aerobreakup of an isolated drop in a uniform gas stream through high fidelity interface-resolved simulation, and to develop physics-based and data-driven point-particle models for Lagrangian spray simulation. The sharp gas-liquid interface is resolved using a mass-momentum consistent VOF method. The open-source Basilisk solver has been used for the present simulations. The computaitonal domain is discretized using a quadtree/octree mesh to allow local refinement of mesh in user defined region. We have started from simulations of water drops at millimeter size and moderate We. The simulation results for drop shape evolution are validated against experiment and an excellent agreement has been achieved. When the drop is suddenly exposed to a uniform gas stream, the drop first deforms to a disk and then to an inflating bag with a peripheral rim. As the bag undergoes inflation, the liquid sheet thickness decreases over time rapidly. Rupture of the bag is initiated through hole nucleation which gradually expands and gets collected into a rim which surrounds the hole. This rim undergoes destabilization thus forming child drops. The high level details of the flow inside the drop has provided crucial insight to improve models to predict the drop shape evolution. The validated simulation approach is then extended to study the sub-millimeter drops. While drop size decreases, the value of Re and Oh decreases if We is kept constant. The purpose is then to investigate the additional effect of Re on drop deformation and critical We. Since the Rayleigh-Taylor instability (RTI) plays a critical role in the drop deformation and bag formation, when the aerodynamic drag coefficient changes with Re, the resulting acceleration and stability of the interface will change as well. Therefore it is important to thoroughly characterize the relation between the drag and the deformation of the drop over time."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["High-fidelity simulation and data-driven modeling of drop aerobreakup."]}]}],"canonical_facts":{"dc:contributor.advisor":["Ling, Stanley (Yue)"],"dc:creator":["Mahmood, Taofiq Hasan, 1992-"],"dc:date.accessioned":["2025-09-05T17:22:47Z"],"dc:date.issued":["2025-05"],"dc:description.abstract":["Aerobreakup of liquid drops is essential to various spray applications like fuel injection, drug delivery, spray painting, among others. Due to the highly transient nature and the wide range of spatial scales involved, experimental diagnostics is challenging and high-fidelity numerical simulation is an important alternative to improve the understanding of drop aerobreakup and improve atomizer design. Drop aerobreakup is controlled by multiple dimensionless parameters, including the Weber (We), Reynolds (Re), Ohnesorge (Oh) numbers and liquid-to-gas density ratio, among which, We is most commonly used to characterize different breakup regimes. The goal of this thesis is to characterize the aerobreakup of an isolated drop in a uniform gas stream through high fidelity interface-resolved simulation, and to develop physics-based and data-driven point-particle models for Lagrangian spray simulation. The sharp gas-liquid interface is resolved using a mass-momentum consistent VOF method. The open-source Basilisk solver has been used for the present simulations. The computaitonal domain is discretized using a quadtree/octree mesh to allow local refinement of mesh in user defined region. We have started from simulations of water drops at millimeter size and moderate We. The simulation results for drop shape evolution are validated against experiment and an excellent agreement has been achieved. When the drop is suddenly exposed to a uniform gas stream, the drop first deforms to a disk and then to an inflating bag with a peripheral rim. As the bag undergoes inflation, the liquid sheet thickness decreases over time rapidly. Rupture of the bag is initiated through hole nucleation which gradually expands and gets collected into a rim which surrounds the hole. This rim undergoes destabilization thus forming child drops. The high level details of the flow inside the drop has provided crucial insight to improve models to predict the drop shape evolution. The validated simulation approach is then extended to study the sub-millimeter drops. While drop size decreases, the value of Re and Oh decreases if We is kept constant. The purpose is then to investigate the additional effect of Re on drop deformation and critical We. Since the Rayleigh-Taylor instability (RTI) plays a critical role in the drop deformation and bag formation, when the aerodynamic drag coefficient changes with Re, the resulting acceleration and stability of the interface will change as well. Therefore it is important to thoroughly characterize the relation between the drag and the deformation of the drop over time."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://hdl.handle.net/2104/13779"],"dc:language.iso":["en"],"dc:rights":["Baylor University works are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. Contact libraryquestions@baylor.edu for inquiries about permission."],"dc:subject":["Aerobreakup.","DNS.","Data-driven modeling."],"dc:title":["High-fidelity simulation and data-driven modeling of drop aerobreakup."],"dc:type":["Thesis"],"thesis:degree_level":["Doctoral"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["Baylor University."]},"updated_at":"2026-07-24T01:08:16Z"}