A Lagrangian, small-scale investigation of turbulent entrainment in an axisymmetric jet

M. Wolf*, B. Lüthi, M. Holzner, A. Liberzon, D. Krug, A. Tsinober

*Corresponding author for this work

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Abstract

Particle tracking velocimetry (PTV) was applied to study turbulent entrainment in an axisymmetric jet at Re = 5000. Several single-point flow statistics are used to characterize the general flow field of our newly designed jet facility, proving that a self-preserving axisymmetric jet could be established. An analysis of the Lagrangian evolution of small scale quantities, such as vorticity and strain, along trajectories passing the entrainment interface is performed. We find that a particle needs on the order of one Kolmogorov time scale to cross the entrainment interface, which is similar to results of grid turbulence without mean shear. Finally, we perform a conditional investigation of invariants of  at the entrainment interface, analyzing joint probability density functions (joint PDFs) evaluated at different times along trajectories crossing the interfacial region.
Original languageEnglish
Article number032053
JournalJournal of physics: Conference series
Volume318
DOIs
Publication statusPublished - 2011
Externally publishedYes
Event13th European Turbulence Conference, ETC 2011 - Warsaw, Poland
Duration: 12 Sep 201115 Sep 2011
Conference number: 13

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