Vector-valued multidimensional signal processing and analysis in the context of fluid flows
Zhong, Jialin
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/22094
Description
Title
Vector-valued multidimensional signal processing and analysis in the context of fluid flows
Author(s)
Zhong, Jialin
Issue Date
1994
Doctoral Committee Chair(s)
Huang, Thomas S.
Adrian, Ronald J.
Department of Study
Electrical and Computer Engineering
Discipline
Electrical Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Engineering, Electronics and Electrical
Physics, Fluid and Plasma
Computer Science
Language
eng
Abstract
This thesis addresses two major issues in the processing and analysis of the velocity fields of fluid obtained either from experiment or from computational fluid dynamics. The first issue is recovering the velocity field from random samples in the context of the Particle Tracking Velocimetry (PTV) or Particle Imaging Velocimetry (PIV) experiment. The theory of recovering vector-valued signals from random point processes is generalized from those for scalar-valued ones. Two interpolation methods are developed based on the physics of fluids. A physically constrained optimal interpolation method is developed when the velocity field is modeled as a random field. A robust one-step interpolation method is developed when the field is modeled as a deterministic function. The second issue in this thesis is the analysis of vortex structures in turbulent fluid flows. A framework for identifying regions of vortices is established, which contains vortex structure modeling, pointwise linear approximation of flow fields, local fluid motion classification, and vortex structure extraction. The model defined in this work is a generic one, with emphasis on the global properties of vortex structures. It is shown that through this pointwise linear approximation, a flow field can be segmented into regions of different topological natures. Local fluid motion is classified by the extended critical point model or by the second invariant of the local deformation tensor. The relationship between these two types of classifiers is explicitly connected. It is also shown, that under the invariant and monotonic criteria, the second invariant II is sufficient to classify the motion into dominating rotational or dominating irrotational motion. The regions of vortex structures are extracted by assimilating spatial points of the same class of fluid motion.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
