Skip to main content
×
Home
    • Aa
    • Aa

Influence of large-scale accelerating motions on turbulent pipe and channel flows

  • Jinyul Hwang (a1), Jin Lee (a1) and Hyung Jin Sung (a1)
Abstract

Direct numerical simulation data from turbulent pipe and channel flows at $\mathit{Re}_{\unicode[STIX]{x1D70F}}\approx 930$ are used to investigate their statistical difference by focusing on large-scale motions (LSMs). The contribution to the bulk production of turbulent kinetic energy shows marked differences in the overlap and core regions. These discrepancies arise from the dominant contributions of the LSMs ( $\unicode[STIX]{x1D706}_{x}>3\unicode[STIX]{x1D6FF}$ ) to the Reynolds shear stress in the channel flow. The spectrum of the net Reynolds shear force reveals that the LSMs accelerate the mean flow in the overlap region. The net force spectrum is further decomposed into the spectra of velocity–vorticity correlations, $\langle v\unicode[STIX]{x1D714}_{z}\rangle$ and $\langle -w\unicode[STIX]{x1D714}_{y}\rangle$ , which are related to the advective vorticity transport and the change-of-scale effect, respectively. The dominance of large-scale accelerating motions (LSAMs) in the overlap region of the channel flow is due to the contribution of $\langle -w\unicode[STIX]{x1D714}_{y}\rangle$ at longer wavelengths ( $\unicode[STIX]{x1D706}_{x}>3\unicode[STIX]{x1D6FF}$ ), The LSAMs are related to the long low-speed regions, and these regions are longer and wider in the channel flow than in the pipe flow. Due to the pipe curvature, the spanwise size of the LSMs is restricted by neighbouring LSMs and the spanwise velocity fluctuations are reduced. The contribution of $\langle -w\unicode[STIX]{x1D714}_{y}\rangle$ to the acceleration is prominent in the channel flow, leading to the dominance of the LSAMs associated with the change-of-scale effect.

Copyright
Corresponding author
Email address for correspondence: hjsung@kaist.ac.kr
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

R. J. Adrian 2007 Hairpin vortex organization in wall turbulence. Phys. Fluids 19 (4), 041301.

N. Afzal 1982 Fully developed turbulent flow in a pipe: an intermediate layer. Ing-Arch. 52, 355377.

J. Ahn , J. H. Lee , S. J. Jang  & H. J. Sung 2013 Direct numerical simulations of fully developed turbulent pipe flows for Re 𝜏 = 180, 544 and 934. Intl J. Heat Fluid Flow 44, 222228.

J. Ahn , J. H. Lee , J. Lee , J.-H. Kang  & H. J. Sung 2015 Direct numerical simulation of a 30R long turbulent pipe flow at Re 𝜏 = 3008. Phys. Fluids 27 (6), 065110.

B. J. Balakumar  & R. J. Adrian 2007 Large- and very-large-scale motions in channel and boundary-layer flows. Phil. Trans. R. Soc. Lond. A 365 (1852), 665681.

M. H. Buschmann  & M. Gad-el Hak 2010 Normal and cross-flow Reynolds stresses: differences between confined and semi-confined flows. Exp. Fluids 49 (1), 213223.

C. Chin , J. P. Monty  & A. Ooi 2014a Reynolds number effects in DNS of pipe flow and comparison with channels and boundary layers. Intl J. Heat Fluid Flow 45, 3340.

D. Chung , I. Marusic , J. P. Monty , M. Vallikivi  & A. J. Smits 2015 On the universality of inertial energy in the log layer of turbulent boundary layer and pipe flows. Exp. Fluids 56 (7), 110.

N. Hutchins  & I. Marusic 2007 Large-scale influences in near-wall turbulence. Phil. Trans. R. Soc. Lond. A 365 (1852), 647664.

K. Kim , S. J. Baek  & H. J. Sung 2002 An implicit velocity decoupling procedure for the incompressible Navier–Stokes equations. Intl J. Numer. Meth. Fluids 38 (2), 125138.

K. C. Kim  & R. J. Adrian 1999 Very large-scale motion in the outer layer. Phys. Fluids 11 (2), 417422.

J. Lee , J. Ahn  & H. J. Sung 2015 Comparison of large-and very-large-scale motions in turbulent pipe and channel flows. Phys. Fluids 27 (2), 025101.

J. H. Lee  & H. J. Sung 2013 Comparison of very-large-scale motions of turbulent pipe and boundary layer simulations. Phys. Fluids 25 (4), 045103.

I. Marusic , R. Mathis  & N. Hutchins 2010 High Reynolds number effects in wall turbulence. Intl J. Heat Fluid Flow 31 (3), 418428.

R. Mathis , J. P. Monty , N. Hutchins  & I. Marusic 2009b Comparison of large-scale amplitude modulation in turbulent boundary layers, pipes, and channel flows. Phys. Fluids 21 (11), 111703.

C. Morrill-Winter  & J. Klewicki 2013 Influences of boundary layer scale separation on the vorticity transport contribution to turbulent inertia. Phys. Fluids 25 (1), 015108.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Fluid Mechanics
  • ISSN: 0022-1120
  • EISSN: 1469-7645
  • URL: /core/journals/journal-of-fluid-mechanics
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×
MathJax

Keywords:

Metrics

Full text views

Total number of HTML views: 5
Total number of PDF views: 225 *
Loading metrics...

Abstract views

Total abstract views: 294 *
Loading metrics...

* Views captured on Cambridge Core between 9th September 2016 - 29th May 2017. This data will be updated every 24 hours.