University of Illinois Urbana-Champaign

Observation of vortex packets in direct numerical simulation of fully turbulent channel flow

Adrian, Ronald J.; Liu, Zhi-Chao

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https://hdl.handle.net/2142/112680

Description

Title
Observation of vortex packets in direct numerical simulation of fully turbulent channel flow
Author(s)
  • Adrian, Ronald J.
  • Liu, Zhi-Chao
Issue Date
2001-10
Keyword(s)
  • Wall Turbulence
  • Wall Eddies
  • Structure
  • Hairpin Vortices
  • Hairpin Vortex Packets
  • Direct Numerical Simulation
Abstract
A number of experimental studies have inferred the existence of packets of inclined, hairpin-like vortices in wall turbulence on the basis of observations made in two-dimensional x-y planes using visualization and particle image velocimetry (PIV). However, there are very few observations of hairpins in existing three-dimensional studies made using direct numerical simulation (DNS), and no such study claims to have revealed packets. We demonstrate, for the first time, the existence of hairpin vortex packets in DNS of turbulent flow. The vortex packet structure found in the present study at low Reynolds number, Ret, = 300, is consistent with and substantiates the observations and the results from two-dimensional PIV measurements at higher Reynolds numbers in channel, pipe and boundary layer flows. Thus, the evidence supports the view that vortex packets are a universal feature of wall turbulence, independent of effects due to boundary layer trips or critical conditions in the aforementioned numerical studies. Visualization of the DNS velocity field and vortices also shows the close association of hairpin packets with long low-momentum streaks and the regions of high Reynolds shear stress.
Publisher
Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report Name or Number
  • TAM R 982
  • 2001-6021
ISSN
0073-5264
Type of Resource
text
Language
eng
Permalink
http://hdl.handle.net/2142/112680
Sponsor(s)/Grant Number(s)
United States National Science Foundation; Office of Naval Researchearch
Copyright and License Information
Copyright 2001 Board of Trustees of the University of Illinois

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