Dynamics of spatially-developing turbulent/turbulent interfaces in the absence of mean shear
File(s)
Accepted version
Author(s)
Alves, Pedro
Zecchetto, Marco
Buxton, Oliver
da Silva, Carlos
Type
Journal Article
Abstract
Spatially-evolving turbulent/turbulent interfaces (TTI) in the absence of mean shear are studied using direct numerical simulations (DNS). To this end, a novel approach was
developed, allowing for six (6) different TTIs to be created with a Taylor-based Reynolds number between 146 ≲ Re𝜆 ≲ 296. The analysis of classical statistics of turbulence intensity, fluctuating vorticity, and integral length scale clearly indicates that one of the two distinct turbulent regions bounding the interface tends to dominate the other one. The halfwidth thickness is found to be dependent on the turbulent properties of each layer, ultimately suggesting that the large-scale quantities dictate the spreading of each turbulent region. Furthermore, conditional profiles of small and large-scale quantities are used to understand the turbulence dynamics separating the two turbulent regions. In contrast, the large-scale properties of the flow do not modify the enstrophy statistics. Additionally, when taking
the difference of fluctuating vorticity levels on each layer ad extremum, profiles typical of turbulent/non-turbulent interfaces (TNTIs) are observed. The budget terms of enstrophy and rate-of-strain magnitude support these findings.
developed, allowing for six (6) different TTIs to be created with a Taylor-based Reynolds number between 146 ≲ Re𝜆 ≲ 296. The analysis of classical statistics of turbulence intensity, fluctuating vorticity, and integral length scale clearly indicates that one of the two distinct turbulent regions bounding the interface tends to dominate the other one. The halfwidth thickness is found to be dependent on the turbulent properties of each layer, ultimately suggesting that the large-scale quantities dictate the spreading of each turbulent region. Furthermore, conditional profiles of small and large-scale quantities are used to understand the turbulence dynamics separating the two turbulent regions. In contrast, the large-scale properties of the flow do not modify the enstrophy statistics. Additionally, when taking
the difference of fluctuating vorticity levels on each layer ad extremum, profiles typical of turbulent/non-turbulent interfaces (TNTIs) are observed. The budget terms of enstrophy and rate-of-strain magnitude support these findings.
Date Issued
2025-11-10
Date Acceptance
2025-07-17
Citation
Journal of Fluid Mechanics, 2025, 1022
ISSN
0022-1120
Publisher
Cambridge University Press
Journal / Book Title
Journal of Fluid Mechanics
Volume
1022
Copyright Statement
© The Author(s), 2025. Published by Cambridge University Press. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Publication Status
Published
Article Number
ARTN A9
Date Publish Online
2025-10-29