Vortex shedding effects in grid-generated turbulence
File(s)Melina Bruce Vassilicos (2016) - VShedding_grids.pdf (3.22 MB)
Accepted version
Author(s)
Melina, G
Bruce, PJK
Vassilicos, C
Type
Journal Article
Abstract
The flow on the centerline of grid-generated turbulence is characterized via hot-wire anemometry for three grids with different geometry: a regular grid (RG60), a fractal grid (FSG17), and a single-square grid (SSG). Due to a higher value of the thickness t0 of its bars, SSG produces greater values of turbulence intensity Tu than FSG17, despite SSG having a smaller blockage ratio. However, the higher Tu for SSG is mainly due to a more pronounced vortex shedding contribution. The effects of vortex shedding suppression along the streamwise direction x are studied by testing a three-dimensional configuration, formed by SSG and a set of four splitter plates detached from the grid (SSG+SP). When vortex shedding is damped, the centerline location of the peak of turbulence intensity xpeak moves downstream and Tu considerably decreases in the production region. For FSG17 the vortex shedding is less intense and it disappears more quickly, in terms of x/xpeak, when compared to all the other configurations. When vortex shedding is attenuated, the integral length scale Lu grows more slowly in the streamwise direction, this being verified both for FSG17 and for SSG+SP. In the production region, there is a correlation between the vortex shedding energy and the skewness and the flatness of the velocity fluctuations. When vortex shedding is not significant, the skewness is highly negative and the flatness is much larger than 3. On the opposite side, when vortex shedding is prominent, the non-Gaussian behavior of the velocity fluctuations becomes masked.
Date Issued
2016-08-01
Date Acceptance
2016-06-03
Citation
Physical Review Fluids, 2016, 1 (4)
ISSN
2469-990X
Publisher
American Physical Society
Journal / Book Title
Physical Review Fluids
Volume
1
Issue
4
Copyright Statement
© 2016 American Physical Society
Sponsor
Commission of the European Communities
Commission of the European Communities
Grant Number
320560
FP7 - 317269
Publication Status
Published
Article Number
044402