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dc.contributor.advisorFasel, Hermann F.en_US
dc.contributor.authorMeitz, Hubert Lorenz, 1964-
dc.creatorMeitz, Hubert Lorenz, 1964-en_US
dc.date.accessioned2013-04-18T09:35:38Z
dc.date.available2013-04-18T09:35:38Z
dc.date.issued1996en_US
dc.identifier.urihttp://hdl.handle.net/10150/282209
dc.description.abstractDirect Numerical Simulations (DMS) of the incompressible Navier-Stokes equations are used to investigate the effect of wall suction on transition in a flat-plate boundary layer. The Navier-Stokes equations are cast in vorticity-velocity formulation. The streamwise and wall-normal derivatives are discretized with compact differences, with a pseudospectral treatment of the spanwise derivatives. Two different methods are used for the time integration. In most calculations, an explicit four-stage Runge Kutta method is used. In some cases, a semi-implicit combination of a three-stage Runge-Kutta- and a Crank-Nicolson method is used. Several case studies are performed. The first case treats the effect of a single row of suction holes, aligned in the spanwise direction, on the evolution of a Tollmien-Schlichting wave. It is found that suction through small holes leads to noticeable nonlinear effects on disturbances with large spanwise wavenumbers. The effect of suction on secondary instability with regards to a large-amplitude Tollmien-Schlichting wave is investigated in the second case study. The suction configurations here are a permeable wall, spanwise slots, and streamwise slots. It is found that sufficiently strong suction suppresses the secondary instability. The different suction configurations are equally effective. The role of the Klebanoff-mode in boundary layer transition is the subject of the third case study. A numerical model of the Klebanoff-mode is presented that agrees well with experimental observations. It is shown how the interaction between the Klebanoff-mode and a Tollmien-Schlichting wave can cause transition. Wall suction is found to be an effective means to prevent transition and maintain laminar flow even in the presence of high-amplitude Klebanoff-mode fluctuations. In the last case study, the limit of very strong suction through holes is investigated. It is shown how the suction holes generate streamwise vortices that can become unstable and lead to bypass transition.
dc.language.isoen_USen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectEngineering, Aerospace.en_US
dc.subjectEngineering, Mechanical.en_US
dc.titleNumerical investigation of suction in a transitional flat-plate boundary layeren_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.identifier.proquest9720582en_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineAerospace and Mechanical Engineeringen_US
thesis.degree.namePh.D.en_US
dc.identifier.bibrecord.b34507425en_US
refterms.dateFOA2018-09-05T15:47:54Z
html.description.abstractDirect Numerical Simulations (DMS) of the incompressible Navier-Stokes equations are used to investigate the effect of wall suction on transition in a flat-plate boundary layer. The Navier-Stokes equations are cast in vorticity-velocity formulation. The streamwise and wall-normal derivatives are discretized with compact differences, with a pseudospectral treatment of the spanwise derivatives. Two different methods are used for the time integration. In most calculations, an explicit four-stage Runge Kutta method is used. In some cases, a semi-implicit combination of a three-stage Runge-Kutta- and a Crank-Nicolson method is used. Several case studies are performed. The first case treats the effect of a single row of suction holes, aligned in the spanwise direction, on the evolution of a Tollmien-Schlichting wave. It is found that suction through small holes leads to noticeable nonlinear effects on disturbances with large spanwise wavenumbers. The effect of suction on secondary instability with regards to a large-amplitude Tollmien-Schlichting wave is investigated in the second case study. The suction configurations here are a permeable wall, spanwise slots, and streamwise slots. It is found that sufficiently strong suction suppresses the secondary instability. The different suction configurations are equally effective. The role of the Klebanoff-mode in boundary layer transition is the subject of the third case study. A numerical model of the Klebanoff-mode is presented that agrees well with experimental observations. It is shown how the interaction between the Klebanoff-mode and a Tollmien-Schlichting wave can cause transition. Wall suction is found to be an effective means to prevent transition and maintain laminar flow even in the presence of high-amplitude Klebanoff-mode fluctuations. In the last case study, the limit of very strong suction through holes is investigated. It is shown how the suction holes generate streamwise vortices that can become unstable and lead to bypass transition.


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