Planar Velocity Measurements in an Incompressible and a Weakly Compressible Mixing Layer
Olsen, Michael Gary
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/2142/83982
Description
Title
Planar Velocity Measurements in an Incompressible and a Weakly Compressible Mixing Layer
Author(s)
Olsen, Michael Gary
Issue Date
1999
Doctoral Committee Chair(s)
Dutton, J. Craig
Department of Study
Mechanical Engineering
Discipline
Mechanical Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Applied Mechanics
Language
eng
Abstract
For the weakly compressible mixing layer, the velocity ratio was 0.53, the density ratio was 0.67, and the convective Mach number was 0.38. At the location where the PIV images were obtained, Rex = 3.7 x 106 , Redw = 1.8 x 105, and Rx/lambda = 18. The planar velocity fields obtained in this study fall into three regimes characterized by the size and number of large-scale structures present. The large-scale rollers are either circular or elliptical, with the elliptical rollers having, in general, horizontal major axes. The transverse velocity fluctuations and Reynolds shear stress are suppressed for the weakly compressible mixing layer as compared to the incompressible case. The spatial correlations of velocity fluctuations are also smaller than those for the incompressible case. The linear stochastic estimate of a roller structure in the weakly compressible mixing layer is elliptical with the major axis oriented in the streamwise direction and with an eccentricity greater than for the incompressible case. The linear stochastic estimate of a braid suggests that the braids are vertically oriented, as opposed to the oblique orientation seen in the incompressible mixing layer. In addition, the braids in the weakly compressible case have a vertically oriented stagnation line, as opposed to the braids in the incompressible mixing layer where stagnation occurs at a point.
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.
