Hostname: page-component-848d4c4894-v5vhk Total loading time: 0 Render date: 2024-07-04T22:25:17.016Z Has data issue: false hasContentIssue false

Localized turbulence structures in transitional rectangular-duct flow

Published online by Cambridge University Press:  08 October 2015

Keisuke Takeishi
Affiliation:
Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan
Genta Kawahara*
Affiliation:
Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan
Hiroki Wakabayashi
Affiliation:
Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan
Markus Uhlmann
Affiliation:
Institute for Hydromechanics, Karlsruhe Institute of Technology, Karlsruhe 76131, Germany
Alfredo Pinelli
Affiliation:
School of Mathematics, Computer Science and Engineering, City University London, London EC1V 0HB, UK
*
Email address for correspondence: [email protected]

Abstract

Direct numerical simulations of transitional flow in a rectangular duct of cross-sectional aspect ratio $A\equiv s/h=1$–9 ($s$ and $h$ being the duct half-span and half-height, respectively) have been performed in the Reynolds number range $\mathit{Re}\equiv u_{b}h/{\it\nu}=650$–1500 ($u_{b}$ and ${\it\nu}$ being the bulk velocity and the kinematic viscosity, respectively) in order to investigate the dependence on the aspect ratio of spatially localized turbulence structures. It was observed that the lowest Reynolds number $\mathit{Re}_{T}$, estimated in a specific way, for localized (transiently sustaining) turbulence decreases monotonically from $\mathit{Re}_{T}=730$ for $A=1$ (square duct) with increasing aspect ratio, and for $A=5$ it nearly attains a minimal value $\mathit{Re}_{T}\approx 670$ that is consistent with the onset Reynolds number of turbulent spots in a plane channel ($A=\infty$). Turbulent states consist of localized structures that undergo a fundamental change around $A=4$. At $\mathit{Re}=\mathit{Re}_{T}$ turbulence for $A=1$$3$ is streamwise-localized similar to turbulent puffs in pipe flow, while for $A=5$–9 turbulence at $\mathit{Re}=\mathit{Re}_{T}$ is also localized in the spanwise direction, similar to turbulent spots in plane channel flow. This structural change in turbulent states at $\mathit{Re}=\mathit{Re}_{T}$ is attributed to the exclusion of turbulence from the vicinity of the duct sidewalls in the case of a wide duct with $A\gtrsim 4$: here the friction length on the sidewalls is so long that the size (around 100 times the friction length) of a self-sustaining minimal flow unit of streamwise vortices and streaks is larger than the duct height and, therefore, it cannot be accommodated.

Type
Papers
Copyright
© 2015 Cambridge University Press 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Aida, H., Tsukahara, T. & Kawaguchi, Y. 2010 DNS of turbulent spot developing into turbulent stripe in plane Poiseuille flow. In Proceedings of ASME 2010 3rd Joint US–European Fluids Engineering Summer Meeting, pp. 21252130.Google Scholar
Avila, K., Moxey, D., Lozar, A., Avila, M., Barkley, D. & Hof, B. 2011 The onset of turbulence in pipe flow. Science 333, 192196.Google Scholar
Avila, M., Mellbovsky, F., Roland, N. & Hof, B. 2013 Streamwise-localized solutions at the onset of turbulence in pipe flow. Phys. Rev. Lett. 110, 224502.CrossRefGoogle ScholarPubMed
Avila, M., Willis, A. P. & Hof, B. 2010 On the transient nature of localized pipe flow turbulence. J. Fluid Mech. 646, 127136.Google Scholar
Brand, E. & Gibson, J. F. 2014 A doubly localized equilibrium solution of plane Couette flow. J. Fluid Mech. 750, R3.Google Scholar
Brosa, U. 1989 Turbulence without strange attractor. J. Stat. Phys. 55, 13031312.Google Scholar
Carlson, D., Widnall, S. & Peeters, M. 1982 Flow-visualization study of transition in plane Poiseuille flow. J. Fluid Mech. 121, 487505.Google Scholar
Dean, R. B. 1978 Reynolds number dependence of skin friction and other bulk flow variables in two-dimensional rectangular duct flow. Trans. ASME J. Fluids Engng 100, 215223.CrossRefGoogle Scholar
Hamilton, J. M., Kim, J. & Waleffe, F. 1995 Regeneration mechanisms of near-wall turbulence structures. J. Fluid Mech. 287, 317348.Google Scholar
Hashimoto, S., Hasobe, A., Tsukahara, T., Kawaguchi, Y. & Kawamura, H. 2009 An experimental study on turbulent-stripe structure in transitional channel flow. In Proceedings of the 6th International Symposium on Turbulence, Heat and Mass Transfer, pp. 193196. Begell House Inc. Google Scholar
Hof, B., Westerweel, J., Schneider, T. M. & Eckhardt, B. 2006 Finite lifetime of turbulence in shear flows. Nature 443, 5962.CrossRefGoogle ScholarPubMed
Jiménez, J. & Moin, P. 1991 The minimal flow unit in near-wall turbulence. J. Fluid Mech. 225, 213240.Google Scholar
Kantz, H. & Grassberger, P. 1985 Repellers, semi-attractors, and long-lived chaotic transients. Physica D 17, 7586.Google Scholar
Kawahara, G., Uhlmann, M. & van Veen, L. 2012 The significance of simple invariant solutions in turbulent flows. Annu. Rev. Fluid Mech. 44, 203225.Google Scholar
Lai, Y.-C. & Winslow, R. L. 1995 Geometric properties of the chaotic saddle responsible for supertransients in spatiotemporal chaotic systems. Phys. Rev. Lett. 74, 52085211.Google Scholar
Lemoult, G., Aider, J.-L. & Wesfreid, J. E. 2013 Turbulent spots in a channel: large-scale flow and self-sustainability. J. Fluid Mech. 731, R1.Google Scholar
de Lozar, A. & Hof, B. 2009 An experimental study of the decay of turbulent puffs in pipe flow. Phil. Trans. R. Soc. Lond. A 367, 589599.Google ScholarPubMed
Mullin, T. 2011 Experimental studies of transition to turbulence in a pipe. Annu. Rev. Fluid Mech. 43, 124.Google Scholar
Nishi, M., Ünsal, B., Durst, F. & Biswas, G. 2008 Laminar-to-turbulent transition of pipe flows through puffs and slugs. J. Fluid Mech. 614, 425446.Google Scholar
Peixinho, J. & Mullin, T. 2006 Decay of turbulence in pipe flow. Phys. Rev. Lett. 96, 094501.Google Scholar
Pinelli, A., Uhlmann, M., Sekimoto, A. & Kawahara, G. 2010 Reynolds number dependence of mean flow structure in square duct turbulence. J. Fluid Mech. 644, 107122.Google Scholar
Tatsumi, T. & Yoshimura, T. 1990 Stability of the laminar flow in a rectangular duct. J. Fluid Mech. 212, 437449.Google Scholar
Uhlmann, M., Kawahara, G. & Pinelli, A. 2010 Traveling-waves consistent with turbulence-driven secondary flow in a square duct. Phys. Fluids 22, 084102.Google Scholar
Uhlmann, M., Pinelli, A., Kawahara, G. & Sekimoto, A. 2007 Marginally turbulent flow in a square duct. J. Fluid Mech. 588, 153162.CrossRefGoogle Scholar
Wygnanski, I. J. & Champagne, F. H. 1973 On transition in a pipe. Part 1. The origin of puffs and slugs and the flow in a turbulent slug. J. Fluid Mech. 59, 281335.Google Scholar
Zammert, S. & Eckhardt, B. 2014 Streamwise and doubly-localised periodic orbits in plane Poiseuille flow. J. Fluid Mech. 761, 348359.CrossRefGoogle Scholar