An experimental study on the flow structure and the instabilities of a flow over a sudden-expansion
Date Issued
2001-07-31
Date
2001-07-31
Author(s)
DOI
892212E002150
Abstract
This project is a continuous work to our
previous research which was a study on an
axisymmetric sudden-expansion flow. This
study further investigates a two-dimensional
flow over a sudden-expansion, with and without
a center-body plate. The flow structures behind
the expansion step, under various expansion
ratios and Reynolds numbers, and flow
instability phenomena are investigated by
experiments. The experimental techniques used
include flow visualization, thermal anemometry,
laser-Doppler velocimetry (LDV) and particle
image velocimetry (PIV). The major parameters
are the Reynolds number and the height of the
sudden expansion.
The first part of this study is to investigate
the flow characteristics for a two-dimensional
flow over a sudden expansion. These properties
include the reattachment length, the flow
symmetry, and the interchanges of the long and
the short recirculation zones. Further, a flow
with a center plate is studied. Comparisons for
these two different flows are made. The detailed
mechanism on the effects of the center plate on
the two recirculation zones, the variations of the
recirculation length with the Reynolds number,
and the effects of the step heights on the
recirculation zones are investigated
experimentally. Moreover, the effects of the
transient large-scale vortex shedding on the flow
structure and the shedding phenomena at further
downstream are studied.
Subjects
Two-dimensional sudden
expansion
expansion
flow pattern
flow
structure
structure
instabilities
Publisher
臺北市：國立臺灣大學應用力學研究所
Type
report
File(s)![Thumbnail Image]()
Loading...
Name
892212E002150.pdf
Size
276.22 KB
Format
Adobe PDF
Checksum
(MD5):8ef7f043ccf13c9abebb93558f0af724