On the theory of wall bounded turbulence : with applications to the problem of viscous drag determination for flows over smooth and rough walls

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Abstract/Contents

Abstract
The study of turbulence has been ongoing for over seven decades now, and it is without a doubt one of the most challenging problems in classical physics. The immense difficulty of understanding and analyzing turbulent flows is why researchers have thrown all their resources at the problem, including supercomputers, in hopes of gaining some insight. While this thesis was written during the era of supercomputers and advanced CFD tools (in other words, in the 21st century), it takes on a different approach- we introduce analytical concepts to deal with turbulent flows, and we do so in a manner that encompasses all Reynolds number flows, from laminar to turbulent. It is our objective to show that the conventional view that turbulence cannot be analyzed analytically and that sophisticated numerical methods must be applied to solve fundamental turbulent flows of Newtonian fluids is not necessarily accurate. In this work, we develop physically meaningful and universal tools to analyze turbulent flows over smooth and rough walls, demonstrate their sufficiency in matching data very well and demonstrate their suitability for practical problems. As of now, direct numerical simulation is only suitable for very low Reynolds number and simple geometry investigations; we do not have enough computational power for the needs of most investigations. However, in far future developments might make it possible to supercompute the movement of each molecule in a fluid, providing a deeper understanding of the fluid dynamics of highly excited fluids. We can, in the meantime, gain a deeper understanding of turbulence through semi-analytical and practical methods. Incorporating semi-analytical models, such as those presented here, into numerical programs will also be extremely helpful for improving the computation of turbulence, since this can reduce computation times and improve the stability of numerical computations.

Description

Type of resource text
Form electronic resource; remote; computer; online resource
Extent 1 online resource.
Place California
Place [Stanford, California]
Publisher [Stanford University]
Copyright date 2023; ©2023
Publication date 2023; 2023
Issuance monographic
Language English

Creators/Contributors

Author Bilgin, Eylül
Degree supervisor Alonso, Juan José, 1968-
Degree supervisor Cantwell, Brian
Thesis advisor Alonso, Juan José, 1968-
Thesis advisor Cantwell, Brian
Thesis advisor Kroo, Ilan
Degree committee member Kroo, Ilan
Associated with Stanford University, School of Engineering
Associated with Stanford University, Department of Aeronautics and Astronautics

Subjects

Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Eylül Bilgin.
Note Submitted to the Department of Aeronautics and Astronautics.
Thesis Thesis Ph.D. Stanford University 2023.
Location https://purl.stanford.edu/kg606df3021

Access conditions

Copyright
© 2023 by Eylul Bilgin
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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