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Three-Dimensional Nature of 2D Hairpin Packet Signatures in a DNS of a Turbulent Boundary Layer

  • S. Rahgozar
  • Y. MacielEmail author
Conference paper
Part of the ERCOFTAC Series book series (ERCO, volume 23)

Abstract

The existence of the outer region “hairpins” and “hairpin packets” is visually assessed in a well-resolved DNS of a zero-pressure-gradient turbulent boundary layer at moderately high Reynolds number. For this purpose, 50 independent 2D streamwise–wall-normal slices at \(Re_{\theta }=4300\) are extracted. The slices are then used to mimic the coarser resolution PIV velocity fields of Adrian et al. J. Fluid Mech, 422:1–54, 2000 [2] using the mimicking procedure of Rahgozar et al. J. Turbul, 14(10):37–66, 2013 [5] based on Gaussian filtering and linear interpolation. Afterwards, in the same manner as Adrian et al. J. Fluid Mech, 422:1–54, 2000 [2], the mimicked fields are inspected in order to discover the signatures of hairpin and hairpin packets. The vortices that are identified as hairpins are then isolated and visualized in three dimensions using the fully resolved DNS data. In agreement with Adrian et al. J. Fluid Mech, 422:1–54, 2000 [2], signatures associated by them to hairpin and hairpin packets are observed frequently in the mimicked planes. However, the 3D character of the 2D signatures is found to be more convoluted than the proposed hairpin packet model.

Keywords

Vortex Tube Hairpin Vortex Interrogation Window Size Vortex Patch Hairpin Packet 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

Financial support from NSERC of Canada is gratefully acknowledged by the authors. They also wish to thank P. Schlatter for sharing his DNS data as well as R.J. Adrian, C.D. Meinhart and C.D. Tomkins for sharing their experimental data.

References

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Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.Department of Mechanical and Materials EngineeringQueen’s UniversityKingstonCanada
  2. 2.Department of Mechanical EngineeringLaval UniversityQuebecCanada

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