Hostname: page-component-848d4c4894-ndmmz Total loading time: 0 Render date: 2024-05-08T11:40:25.719Z Has data issue: false hasContentIssue false
  • English
  • Français

On the physical nature of the turbulent/turbulent interface

Published online by Cambridge University Press:  23 May 2022

Krishna S. Kankanwadi Open the ORCID record for Krishna S. Kankanwadi [Opens in a new window]  and
Oliver R.H. Buxton Open the ORCID record for Oliver R.H. Buxton [Opens in a new window]
Krishna S. Kankanwadi
Affiliation:
Department of Aeronautics, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
Oliver R.H. Buxton*
Affiliation:
Department of Aeronautics, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
*
†Email address for correspondence: o.buxton@imperial.ac.uk
Get access Rights & Permissions [Opens in a new window]

Abstract

The existence of a turbulent/turbulent interface (TTI) has recently been verified in the far wake of a circular cylinder exposed to free-stream turbulence (Kankanwadi & Buxton, J. Fluid Mech., vol. 905, 2020, p. A35). This study aims to understand the physics within the TTI. The wake boundary, approximately 40 diameters downstream of a circular cylinder subjected to grid-generated turbulence, was investigated through simultaneous cinematographic, stereoscopic particle image velocimetry and planar laser induced fluorescence experiments. With no grid placed upstream of the cylinder, the behaviour of the resultant interface, our closest approximation to a turbulent/non-turbulent interface, exactly matched what is observed in existing literature. When background turbulence is present, viscous action is no longer the only method by which enstrophy is transported to the background fluid, unlike for turbulent/non-turbulent interfaces. The presence of rotational fluid on both sides of the TTI allows the vorticity stretching term of the enstrophy budget equation to be the dominant actor in this process. The role of viscosity within a TTI is greatly diminished as the vorticity stretching term takes over responsibilities for enstrophy production. The turbulent strain rate normal to the TTI was found to be enhanced in the interfacial region. Decomposing the vorticity stretching term into components aligned with the three principal strain-rate directions, it was found that the term most aligned with the interface-normal direction contributed to the largest share of enstrophy production. This indicates that better ‘organised’ vorticity on the wake side of the interface yields the enstrophy amplification leading to the previously discovered enstrophy jump across the TTI by Kankanwadi & Buxton (J. Fluid Mech., vol. 905, 2020, p. A35).

JFM classification

Wakes/Jets: Wakes Mixing: Turbulent mixing
Type
JFM Papers
Information
Journal of Fluid Mechanics , Volume 942 , 10 July 2022 , A31
Check for updates
Copyright
© The Author(s), 2022. Published by 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

REFERENCES

Atreya, S.K., Wong, M.H., Owen, T.C., Mahaffy, P.R., Niemann, H.B., de Pater, I., Drossart, P. & Encrenaz, T. 1999 A comparison of the atmospheres of Jupiter and Saturn: deep atmospheric composition, cloud structure, vertical mixing, and origin. Planet. Space Sci. 47 (10), 1243–1262.CrossRefGoogle ScholarPubMed
Betchov, R. 1956 An inequality concerning the production of vorticity in isotropic turbulence. J. Fluid Mech. 1 (5), 497–504.CrossRefGoogle Scholar
Bisset, D.K., Hunt, J.C.R. & Rogers, M.M. 2002 The turbulent/non-turbulent interface bounding a far wake. J. Fluid Mech. 451, 383–410.CrossRefGoogle Scholar
Buxton, O.R.H., Breda, M. & Dhall, K. 2019 Importance of small-scale anisotropy in the turbulent/nonturbulent interface region of turbulent free shear flows. Phys. Rev. Fluids 4 (3), 034603.CrossRefGoogle Scholar
Ching, C.Y., Fernando, H.J.S. & Robles, A. 1995 Breakdown of line plumes in turbulent environments. J. Geophys. Res.: Oceans 100 (C3), 4707–4713.CrossRefGoogle Scholar
Cimarelli, A., Cocconi, G., Frohnapfel, B. & De Angelis, E. 2015 Spectral enstrophy budget in a shear-less flow with turbulent/non-turbulent interface. Phys. Fluids 27 (12), 125106.CrossRefGoogle Scholar
Corrsin, S. & Kistler, A.L. 1955 Free-stream boundaries of turbulent flows. NACA technical report 1244.Google Scholar
Eames, I., Jonsson, C. & Johnson, P.B. 2011 The growth of a cylinder wake in turbulent flow. J. Turbul. 12, 39.CrossRefGoogle Scholar
Elsinga, G.E. & da Silva, C.B. 2019 How the turbulent/non-turbulent interface is different from internal turbulence. J. Fluid Mech. 866, 216–238.CrossRefGoogle Scholar
Ganapathisubramani, B., Lakshminarasimhan, K. & Clemens, N.T. 2007 Determination of complete velocity gradient tensor by using cinematographic stereoscopic PIV in a turbulent jet. Exp. Fluids 42, 923–939.CrossRefGoogle Scholar
Gaskin, S.J., McKernan, M. & Xue, F. 2004 The effect of background turbulence on jet entrainment: an experimental study of a plane jet in a shallow coflow. J. Hydraul Res. 42 (5), 533–542.CrossRefGoogle Scholar
Holzner, M., Liberzon, A., Nikitin, N., Kinzelbach, W. & Tsinober, A. 2007 Small-scale aspects of flows in proximity of the turbulent/nonturbulent interface. Phys. Fluids 19 (7), 071702.CrossRefGoogle Scholar
Hunt, J.C.R., Eames, I., Westerweel, J., Davidson, P.A., Voropayev, S., Fernando, J. & Braza, M. 2010 Thin shear layers – the key to turbulence structure? J. Hydro-Environ. Res. 4 (2), 75–82. Special Issue II on Shallow Flows - Dedicated to Prof. Gerhard H. Jirka.CrossRefGoogle Scholar
Ishihara, T., Kaneda, Y. & Hunt, J.C.R. 2013 Thin shear layers in high Reynolds number turbulence - DNS results. Flow Turbul. Combust. 91 (4), 895–929.CrossRefGoogle Scholar
Kankanwadi, K.S. & Buxton, O.R.H. 2020 Turbulent entrainment into a cylinder wake from a turbulent background. J. Fluid Mech. 905, A35.CrossRefGoogle Scholar
de Rooy, W.C., Bechtold, P., Fröhlich, K., Hohenegger, C., Jonker, H., Mironov, D., Pier Siebesma, A., Teixeira, J. & Yano, J.-I. 2013 Entrainment and detrainment in cumulus convection: an overview. Q. J. R. Meteorol. Soc. 139 (670), 1–19.CrossRefGoogle Scholar
da Silva, C.B., Hunt, J.C.R., Eames, I. & Westerweel, J. 2014 Interfacial layers between regions of different turbulence intensity. Annu. Rev. Fluid Mech. 46 (1), 567–590.CrossRefGoogle Scholar
de Silva, C.M., Philip, J. & Marusic, I. 2013 Minimization of divergence error in volumetric velocity measurements and implications for turbulence statistics. Exp. Fluids 54, 1557.CrossRefGoogle Scholar
da Silva, C.B. & dos Reis, R.J.N. 2011 The role of coherent vortices near the turbulent/non-turbulent interface in a planar jet. Phil. Trans. R. Soc. A: Math. Phys. Engng Sci. 369 (1937), 738–753.CrossRefGoogle Scholar
Silva, T.S., Zecchetto, M. & Da Silva, C.B. 2018 The scaling of the turbulent/non-turbulent interface at high Reynolds numbers. J. Fluid Mech. 843, 156–179.CrossRefGoogle Scholar
Taveira, R.R. & da Silva, C.B. 2014 Characteristics of the viscous superlayer in shear free turbulence and in planar turbulent jets. Phys. Fluids 26 (2), 021702.CrossRefGoogle Scholar
Taylor, G.I. 1938 Production and dissipation of vorticity in a turbulent fluid. Proc. R. Soc. Lond. Ser. A - Math. Phys. Sci. 164 (916), 15–23.Google Scholar
Van Reeuwijk, M. & Holzner, M. 2013 The turbulence boundary of a temporal jet. J. Fluid Mech. 739, 254–275. arXiv:1304.0476.CrossRefGoogle Scholar
Watanabe, T., Sakai, Y., Nagata, K., Ito, Y. & Hayase, T. 2014 Vortex stretching and compression near the turbulent/non-turbulent interface in a planar jet. J. Fluid Mech. 758, 754–785.CrossRefGoogle Scholar
Watanabe, T., Zhang, X. & Nagata, K. 2018 Turbulent/non-turbulent interfaces detected in DNS of incompressible turbulent boundary layers. Phys. Fluids 30 (3), 035102.CrossRefGoogle Scholar
Westerweel, J., Fukushima, C., Pedersen, J. & Hunt, J.C.R. 2005 Mechanics of the turbulent-nonturbulent interface of a jet. Phys. Rev. Lett. 95 (17), 199902.CrossRefGoogle ScholarPubMed