The significance of hairpin vortices in turbulent boundary layers
2020 (English)In: ETC 2013 - 14th European Turbulence Conference, Zakon Group LLC , 2020Conference paper, Published paper (Refereed)
Abstract [en]
The elementary question whether hairpin vortices constitute an inherent, universal structure of wall turbulence at moderate and high Reynolds numbers (Re) is addressed in this study. The downstream evolution of a single, artificial hairpin vortex is first studied in a mean shear flow to investigate possible decay and package-creation processes under high Re conditions. In a second step, hairpin-dominated flow in a transitional turbulent boundary layer is considered, whereas the lifetime of individual vortices and possible connection mechanisms are evaluated. The statistics obtained from this flow regime will be compared with reference data from turbulent-boundary-layer studies employing different transition mechanisms. Vortex eduction will be applied to comprehend the evolution from a well organized to a more chaotic state. The results could explain discrepancies in boundary-layer data close to transition and will contribute to the discussion about the relevance of hairpin-like structures in fully developed wall turbulence.
Place, publisher, year, edition, pages
Zakon Group LLC , 2020.
Keywords [en]
Boundary layer flow, Boundary layers, Reynolds number, Shear flow, Turbulence, Turbulent flow, Vortex flow, Creation process, Hairpin vortices, High Reynolds number, Reference data, Transition mechanism, Turbulent boundary layers, Universal structures, Wall turbulence, Atmospheric thermodynamics
National Category
Fluid Mechanics
Identifiers
URN: urn:nbn:se:kth:diva-274276Scopus ID: 2-s2.0-85085779430OAI: oai:DiVA.org:kth-274276DiVA, id: diva2:1453576
Conference
14th European Turbulence Conference, ETC 2013, 1 September 2013 through 4 September 2013
Note
QC 20200710
2020-07-102020-07-102025-02-09Bibliographically approved