Turbulent entrainment from a turbulent background
File(s)
Accepted version
Author(s)
Kankanwadi, Krishna
Buxton, Oliver
Type
Conference Paper
Abstract
Simultaneous particle image velocimetry (PIV) andplanar laser induced fluorescence (PLIF) measurementswere conducted in order to investigate the effects of back-ground turbulence on the entrainment process as well ason the behaviour of the wake interface. Previous studieshave highlighted the importance of length scale as well asturbulence intensity in the background flow. This paperreports on a parametric study examining entrainment intothe wake of a circular cylinder by independently varyingbackground turbulence parameters through the use of tur-bulence generating grids. Despite the availability of tur-bulent rotational fluid on both sides of the interface, theclassical turbulent/non-turbulent interface result of an en-strophy jump is reproduced, even in the harshest incomingfree-stream turbulence conditions. Examining the tortuos-ity, reveals that both length scale and turbulence intensityin the background turbulence act to increase the interfacesurface area. Furthermore, the entrainment process is foundto be greatly sensitive to the turbulence intensity of the sub-jected free-stream turbulence. However, despite an increasein surface area, a net reduction in mean entrainment massflux is observed with increased intensity in the backgroundturbulence. Examining the mass flux PDFs, reveals that thisbehaviour is a result of substantial, yet infrequent detrain-ment events.
Date Issued
2019-08-05
Date Acceptance
2019-05-17
Citation
Proceedings of TSFP-11 (2019), 2019
Journal / Book Title
Proceedings of TSFP-11 (2019)
Copyright Statement
© 2019 The Author(s)
Source
Eleventh International Symposium on Turbulence and Shear Flow Phenomena
Publication Status
Published
Start Date
2019-07-30
Finish Date
2019-08-02
Coverage Spatial
Southampton, UK
Date Publish Online
2019-08-05