Direct numerical simulation of free-surface and interfacial flow using the VOF method: cavitating bubble clouds and phase change

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dc.contributor.advisorZaleski, Stéphaneen_ZA
dc.contributor.advisorMalan, Arnaud Gen_ZA
dc.contributor.advisorRousseau, Pieter Gen_ZA
dc.contributor.authorMalan, Leonen_ZA
dc.date.accessioned2018-05-03T12:28:23Z
dc.date.available2018-05-03T12:28:23Z
dc.date.issued2018en_ZA
dc.description.abstractDirect Numerical Simulation of two-phase ow is used extensively for engineering research and fundamental fluid physics studies. This study is based on the Volume-Of-Fluid (VOF) method, originally created by Hirt and Nicols. This method has gained increased popularity, especially when geometric advection techniques are used coupled with a planar reconstruction of the interface. The focus of the first part of this work is to investigate the hydrodynamics of isothermal cavitation in large bubble clouds, which originated from a larger study of micro-spalling, conducted by the French CEA. A method to deal with volume-changing vapour cavities, or pores, was formulated and implemented in an existing code, PARIS. The ow is idealized by assuming an inviscid liquid, negligible thermal effects and vanishing vapour pressure. A novel investigation of bubble cloud interaction in an expanding liquid using Direct or Detailed Numerical Simulation is presented. The simulation results reveal a pore competition, which is characterised by the Weber number in the ow. In the second part of the study the governing equations are extended to describe incompressible ow with phase change. The description of the work commences with the derivation of the governing equations. Following this, a novel, geometric based, VOF solution method is proposed. In this method a novel way of advecting the VOF function is invented, which treats both mass and energy conservation in conservative form. New techniques include the advection of the interface in a discontinuous velocity field. The proposed algorithms are consistent and elegant, requiring minimal modifications to the existing code. Numerical experiments demonstrate accuracy, robustness and generality. This is viewed as a significant fundamental development in the use of VOF methods to model phase change.en_ZA
dc.identifier.apacitationMalan, L. (2018). <i>Direct numerical simulation of free-surface and interfacial flow using the VOF method: cavitating bubble clouds and phase change</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering. Retrieved from http://hdl.handle.net/11427/27898en_ZA
dc.identifier.chicagocitationMalan, Leon. <i>"Direct numerical simulation of free-surface and interfacial flow using the VOF method: cavitating bubble clouds and phase change."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering, 2018. http://hdl.handle.net/11427/27898en_ZA
dc.identifier.citationMalan, L. 2018. Direct numerical simulation of free-surface and interfacial flow using the VOF method: cavitating bubble clouds and phase change. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Malan, Leon AB - Direct Numerical Simulation of two-phase ow is used extensively for engineering research and fundamental fluid physics studies. This study is based on the Volume-Of-Fluid (VOF) method, originally created by Hirt and Nicols. This method has gained increased popularity, especially when geometric advection techniques are used coupled with a planar reconstruction of the interface. The focus of the first part of this work is to investigate the hydrodynamics of isothermal cavitation in large bubble clouds, which originated from a larger study of micro-spalling, conducted by the French CEA. A method to deal with volume-changing vapour cavities, or pores, was formulated and implemented in an existing code, PARIS. The ow is idealized by assuming an inviscid liquid, negligible thermal effects and vanishing vapour pressure. A novel investigation of bubble cloud interaction in an expanding liquid using Direct or Detailed Numerical Simulation is presented. The simulation results reveal a pore competition, which is characterised by the Weber number in the ow. In the second part of the study the governing equations are extended to describe incompressible ow with phase change. The description of the work commences with the derivation of the governing equations. Following this, a novel, geometric based, VOF solution method is proposed. In this method a novel way of advecting the VOF function is invented, which treats both mass and energy conservation in conservative form. New techniques include the advection of the interface in a discontinuous velocity field. The proposed algorithms are consistent and elegant, requiring minimal modifications to the existing code. Numerical experiments demonstrate accuracy, robustness and generality. This is viewed as a significant fundamental development in the use of VOF methods to model phase change. DA - 2018 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2018 T1 - Direct numerical simulation of free-surface and interfacial flow using the VOF method: cavitating bubble clouds and phase change TI - Direct numerical simulation of free-surface and interfacial flow using the VOF method: cavitating bubble clouds and phase change UR - http://hdl.handle.net/11427/27898 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/27898
dc.identifier.vancouvercitationMalan L. Direct numerical simulation of free-surface and interfacial flow using the VOF method: cavitating bubble clouds and phase change. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering, 2018 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/27898en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Mechanical Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMechanical Engineeringen_ZA
dc.titleDirect numerical simulation of free-surface and interfacial flow using the VOF method: cavitating bubble clouds and phase changeen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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