Study of the effects of centrifugal instabilities on flow in a 40 to 1 aspect ratio rectangular curved channel, for Dean numbers from 35 to fully turbulent conditions
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Authors
Fields, William A.
Subjects
Dean Vortices
Dean Number
Rectangular Curved Channel
Dean Number
Rectangular Curved Channel
Advisors
Ligrani, P. M.
Date of Issue
1990-12
Date
December 1990
Publisher
Monterey, CA; Naval Postgraduate School
Language
Abstract
The development and structure of Dean vortices in a high aspect ratio curved channel were measured and studied for Dean numbers from 35 to fully turbulent conditions. Mean vorticity components were determined from measurements of the three components of mean velocity, which were measured using a miniature five-hole pressure probe. Streamwise, radial and spanwise vorticity components measured 120 deg from the start of curvature, show evidence of Dean vortices in the time-averaged flow field. Peak streamwise and peak spanwise vorticity, as well as streamwise circulation, generally increase as the Dean number increases from 60 to 240. Peak radial vorticity increases as Dean numbers vary from 60 to about 160. Spectra obtained from hot-wire probes show evidence of different frequency events, including twisting and undulation. Twisting is apparent for Dean numbers of 135 to 160 while undulation is observed at lower Dean numbers. Flow visualization results illustrate a variety of time dependent events in the channel.
Type
Thesis
Description
Series/Report No
Department
Mechanical Engineering
Organization
Identifiers
NPS Report Number
Sponsors
Funding
Format
xv, 175 p. ill.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.