Controlling Secondary Flows in Turbulent Taylor-Couette Flow Using Surface Heterogeneity
| dc.contributor.advisor | Ostilla-Mónico, Rodolfo | |
| dc.contributor.committeeMember | Alba, Kamran | |
| dc.contributor.committeeMember | Liu, Dong | |
| dc.contributor.committeeMember | Floryan, Daniel | |
| dc.contributor.committeeMember | Chen, Guoning | |
| dc.creator | Jeganathan, Vignesh | |
| dc.creator.orcid | 0000-0002-1663-1240 | |
| dc.date.accessioned | 2023-06-02T17:18:07Z | |
| dc.date.created | December 2022 | |
| dc.date.issued | 2022-12-13 | |
| dc.date.updated | 2023-06-02T17:18:10Z | |
| dc.description.abstract | Turbulent shear flows are abundant in geophysical and astrophysical systems and in engineering-technology applications. They are often riddled with large-scale secondary flows that drastically modify the characteristics of the primary stream, preventing or enhancing mixing, mass, and heat transfer. In this thesis, we study the possibility of modifying these secondary flows by using stress reducing surfaces including free-slip and superhydrophobic surface treatments that reduce the local shear. We focus on the canonical problem of Taylor-Couette flow, the flow between two coaxial and independently-rotating cylinders, which has robust pinned secondary structures called Taylor rolls that persist even at significant levels of turbulence. It is shown through experiments and simulations that stress reducing surfaces arranged in a spanwise manner destructively interfere with Taylor rolls by inducing additional secondary flows through surface heterogeneity, as long as the structure size can be fixed. Simulations also find that slanted free-slip surfaces, when applied at certain angles and wavelengths, induce a velocity that causes the large-scale structures to move when the domain is periodic. The minimum slip-lengths of the treatment required for this flow control to work are determined and rationalized, and their effectiveness beyond the Reynolds numbers studied here is also discussed. We also explore a novel framework for understanding the origins of Taylor rolls through a two-way coupling between velocities caused by Coriolis forces, and apply it to other flows finding that the framework is not valid. | |
| dc.description.department | Mechanical Engineering, Department of | |
| dc.format.digitalOrigin | born digital | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.citation | Portions of this document appear in: Jeganathan, Vignesh, Kamran Alba, and Rodolfo Ostilla-Mónico. "Controlling secondary flows in Taylor–Couette flow using stress-free boundary conditions." Journal of Fluid Mechanics 922 (2021): A17; and in: Jeganathan, Vignesh, Kamran Alba, and Rodolfo Ostilla-Mónico. "Exploring the origin of turbulent Taylor rolls." Philosophical Transactions of the Royal Society A 381, no. 2243 (2023): 20220130. | |
| dc.identifier.uri | https://hdl.handle.net/10657/14389 | |
| dc.language.iso | eng | |
| dc.rights | The author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. UH Libraries has secured permission to reproduce any and all previously published materials contained in the work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s). | |
| dc.subject | Taylor-Couette flow | |
| dc.subject | Turbulence | |
| dc.subject | Instability control | |
| dc.subject | Drag reduction | |
| dc.subject | Origin of Taylor rolls | |
| dc.title | Controlling Secondary Flows in Turbulent Taylor-Couette Flow Using Surface Heterogeneity | |
| dc.type.dcmi | Text | |
| dc.type.genre | Thesis | |
| dcterms.accessRights | The full text of this item is not available at this time because the student has placed this item under an embargo for a period of time. The Libraries are not authorized to provide a copy of this work during the embargo period. | |
| local.embargo.lift | 2024-12-01 | |
| local.embargo.terms | 2024-12-01 | |
| thesis.degree.college | Cullen College of Engineering | |
| thesis.degree.department | Mechanical Engineering, Department of | |
| thesis.degree.discipline | Mechanical Engineering | |
| thesis.degree.grantor | University of Houston | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy |