Author ORCID Identifier
Date Available
11-5-2025
Year of Publication
2025
Document Type
Doctoral Dissertation
Degree Name
Doctor of Philosophy (PhD)
College
Engineering
Department/School/Program
Mechanical Engineering
Faculty
Sean Bailey
Faculty
Jonathan Wenk
Abstract
This dissertation investigates the scaling behavior, structural organization, and modeling of turbulence in wall-bounded flows across a wide range of Reynolds numbers and surface conditions. Through high-resolution experimental studies in zero-pressure- gradient turbulent boundary layers and pipe flows (2000 < Reτ < 38 200), the wall- dependence of turbulent length scales is examined with a focus on both small-scale dissipative motions and large-scale structures. When external intermittency is properly accounted for, dissipative motions are shown to obey inner scaling even in outer- scaled regions, while large-scale motions exhibit outer scaling behavior deep into the inner region. These findings are consistent across internal (pipe) and external (boundary layer) flows and are reflected in distinct features of the longitudinal wavenumber spectrum.
The dissertation also explores the development of a turbulent boundary layer transitioning from a smooth solid wall to a liquid surface. An internal boundary layer forms in response to stochastic surface waves, resulting in increased turbulence intensity and displaced momentum relative to solid-wall cases. Near the liquid surface, turbulence generation aligns with wavenumbers corresponding to the surface waves, introducing distinct small-scale dynamics. Despite significant differences in spectral and Reynolds stress characteristics near the interface, the turbulence further from the surface asymptotically resembles that over solid walls. A surrogate friction velocity is proposed to successfully scale both the Kolmogorov length scale and streamwise Reynolds stress within this internal layer, revealing logarithmic scaling behavior akin to high Reynolds number overlap regions.
Finally, a spectral model is developed to describe the streamwise velocity spectrum and Reynolds stress in pipe flow at arbitrarily large Reynolds numbers. The model decomposes the spectrum into contributions from streaks, large-scale motions, very-large-scale motions, and incoherent turbulence. While simplified, the model accurately reproduces key Reynolds stress features – such as the inner peak, outer peak, and logarithmic region, highlighting the interplay between inner- and outer- scaled eddy structures and wall proximity. With minimal modifications, the model shows promise for extending to other canonical wall-bounded flows, including boundary layers and channels.
Together, these studies enhance the understanding of turbulent structure across diverse wall-bounded configurations and contribute practical tools for interpreting and modeling turbulence in complex flow environments.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2025.459
Funding Information
-
National Aeronautics and Space Administration,Award no. 80NSSC19M0144
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Established Program to Stimulate Competitive Research award no. 80NSSC20M0162
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Recommended Citation
Gustenyov, Nikolay, "Scaling Investigations of Wall-Bounded Turbulent Flow" (2025). Theses and Dissertations--Mechanical Engineering. 247.
https://uknowledge.uky.edu/me_etds/247
