Type of Document Master's Thesis Author Ortega Lopez, Miguel Dario Author's Email Address email@example.com URN etd-05052009-121041 Title Exploring and Envisioning Periodic Laminar Flow Around a Cylinder Degree Master of Science Department Engineering Science and Mechanics Advisory Committee
Advisor Name Title Kriz, Ronald D. Committee Chair Dancey, Clinton L. Committee Co-Chair Ragab, Saad A. Committee Member Keywords
- qualitative analysis
- second invariant of the velocity gradient
Date of Defense 2009-04-24 Availability unrestricted AbstractIt is well known that for small Reynolds numbers, flow around a cylinder is laminar and stable.
For larger Reynolds numbers, although the flow regime remains laminar, the formation of
complex periodic structures appear downstream. The cyclic nature of this periodic flow is well
characterized by the vortex shedding frequency and Strouhal number. However, complexities of
these periodic structures downstream continue to be a topic of research. Periodic laminar 2D
incompressible viscous flow around a cylinder is simulated using OpenFoam, an open source
computational fluid dynamics program. To better understand these complex structures
downstream, a customized computer graphical tool, VerFlow-V.01, was created to analyze and
study OpenFoam simulation results. This study includes an investigation of calculating the
details of drag and lift coefficients for the cylinder using mathematical models that integrate
properties in subdomains, an approach not previously explored to the knowledge of the author.
Numerical integration is accomplished using a finite difference approach for solving surface and
contour integrals in subdomains of interest. Special attention is given to pressure and to the
second invariant of the velocity gradient, as they have a clear mathematical relationship, which is
consistent with results previously published. A customized visual data analysis tool, called
VerFlow-V.01, allowed investigators to compare simulation data variables in a variety of useful
ways, revealing details not previously understood. Main subroutines and a user’s manual are
included as appendices to encourage reproducibility and future development of the numerical,
analytical and graphical models developed here. Together these models resulted in a new
understanding of periodic laminar flow around a cylinder. A unique approach was developed to
qualitatively understand the origins of drag and lift coefficients associated with properties
mapped as images in subdomains of interest downstream. These results explain the development
of convergent, eddy, and stream zones embedded in flow fields downstream.
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access 01e_Exploring_and_Envisioning_Periodic_Laminar_Flow.pdf 4.49 Mb 00:20:48 00:10:41 00:09:21 00:04:40 00:00:23 A1.1_reverse_FS.wmv 696.93 Kb 00:03:13 00:01:39 00:01:27 00:00:43 00:00:03 A4.1_Forces_FS.mov 428.31 Kb 00:01:58 00:01:01 00:00:53 00:00:26 00:00:02 A4.2_Rect_FS.mov 3.59 Mb 00:16:36 00:08:32 00:07:28 00:03:44 00:00:19 A4.3_EntireDomain_FS.mov 4.43 Mb 00:20:29 00:10:32 00:09:13 00:04:36 00:00:23 A4.4_stagQDragFull_FS.mov 9.29 Mb 00:43:00 00:22:07 00:19:21 00:09:40 00:00:49 A4.5_stagQLiftFull_FS.mov 8.01 Mb 00:37:05 00:19:04 00:16:41 00:08:20 00:00:42 A4.6_StagVortVelVectors_FS.mov 7.92 Mb 00:36:41 00:18:52 00:16:30 00:08:15 00:00:42
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