Scale dependence of the alignment between strain rate and rotation in turbulent shear flow

dc.contributor.utaustinauthorKAUST Supercomputing Laboratoryen_US
dc.creatorFiscaletti, D.en_US
dc.creatorElsinga, G. E.en_US
dc.creatorAttili, A.en_US
dc.creatorBisetti, F.en_US
dc.creatorBuxton, O. R. H.en_US
dc.description.abstractThe scale dependence of the statistical alignment tendencies of the eigenvectors of the strain-rate tensor e(i), with the vorticity vector omega, is examined in the self-preserving region of a planar turbulent mixing layer. Data from a direct numerical simulation are filtered at various length scales and the probability density functions of the magnitude of the alignment cosines between the two unit vectors vertical bar e(i) . (omega) over cap vertical bar are examined. It is observed that the alignment tendencies are insensitive to the concurrent large-scale velocity fluctuations, but are quantitatively affected by the nature of the concurrent large-scale velocity-gradient fluctuations. It is confirmed that the small-scale (local) vorticity vector is preferentially aligned in parallel with the large-scale (background) extensive strain-rate eigenvector e(1), in contrast to the global tendency for omega to be aligned in parallelwith the intermediate strain-rate eigenvector [Hamlington et al., Phys. Fluids 20, 111703 (2008)]. When only data from regions of the flow that exhibit strong swirling are included, the so-called high-enstrophy worms, the alignment tendencies are exaggerated with respect to the global picture. These findings support the notion that the production of enstrophy, responsible for a net cascade of turbulent kinetic energy from large scales to small scales, is driven by vorticity stretching due to the preferential parallel alignment between omega and nonlocal e(1) and that the strongly swirling worms are kinematically significant to this process.en_US
dc.description.departmentAerospace Engineeringen_US
dc.description.sponsorshipKAUST Supercomputing Laboratoryen_US
dc.identifier.citationFiscaletti, Daniele, G. E. Elsinga, Antonio Attili, Fabrizio Bisetti, and O. R. H. Buxton. "Scale dependence of the alignment between strain rate and rotation in turbulent shear flow." Physical Review Fluids 1, no. 6 (2016): 064405.en_US
dc.relation.ispartofUT Faculty/Researcher Worksen_US
dc.relation.ispartofserialPhysical Review Fluidsen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjecthigh reynolds-numberen_US
dc.subjecthomogeneous turbulenceen_US
dc.subjectisotropic turbulenceen_US
dc.subjectmixing layeren_US
dc.subjectincompressible fluiden_US
dc.titleScale dependence of the alignment between strain rate and rotation in turbulent shear flowen_US

Access full-text files

Original bundle

Now showing 1 - 1 of 1
Thumbnail Image
645.27 KB
Adobe Portable Document Format

License bundle

Now showing 1 - 1 of 1
No Thumbnail Available
1.65 KB
Plain Text