Journal article
Flow patterns around confined low-aspect-ratio obstacles
Experiments in fluids, Vol.64(8), 139
2023
DOI: 10.1007/s00348-023-03675-y
Abstract
An experimental study was conducted on the wakes around three different obstacles confined between two parallel walls: semi-ellipsoids with the major axes of the base ellipses aligned in the streamwise and transverse directions, and a sphere. The Reynolds number was
1.78
×
10
4
based on obstacle height,
H
. Common to each of these geometries is a convex surface of the obstacle intersecting one or more boundaries, which was shown to result in a wall jet in the vicinity of the junction. Large streamwise counter-rotating vortex structures were found to be a robust feature of the wakes, which are referred to as
lobes
, due to their resemblance to previously coined lobe structures identified in the wake of a deeply submerged sphere.
Inner lobe
structures, of opposite sense to the primary lobes, were also observed in all cases, and it is proposed that the primary and inner lobe structures are formed by the wall jet deforming vorticity shed by the obstacle into a hairpin-like loop. Wavelet analysis of velocity time series on both sides of the wake revealed approximately antisymmetric vortex shedding in the ellipsoid wakes; however, intermittent in-phase shedding was observed in the wake of the sphere. This study showed that the shape of the obstacle junction (convex vs. flat) plays an important role in the behavior of the wake.
Details
- Title: Subtitle
- Flow patterns around confined low-aspect-ratio obstacles
- Creators
- Seyed M. Hajimirzaie - University of IowaJames H. J. Buchholz - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Experiments in fluids, Vol.64(8), 139
- Publisher
- Springer Berlin Heidelberg
- DOI
- 10.1007/s00348-023-03675-y
- ISSN
- 0723-4864
- eISSN
- 1432-1114
- Grant note
- CBET-1033732; CBET-1033732 / National Science Foundation (http://dx.doi.org/10.13039/100000001)
- Language
- English
- Date published
- 2023
- Academic Unit
- Mechanical Engineering
- Record Identifier
- 9984446075602771
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