Hostname: page-component-848d4c4894-8kt4b Total loading time: 0 Render date: 2024-07-07T09:22:23.476Z Has data issue: false hasContentIssue false

Decaying turbulence in a stratified fluid of high Prandtl number

Published online by Cambridge University Press:  12 July 2019

Shinya Okino*
Affiliation:
Department of Mechanical Engineering and Science, Kyoto University, Kyoto 615-8540, Japan
Hideshi Hanazaki
Affiliation:
Department of Mechanical Engineering and Science, Kyoto University, Kyoto 615-8540, Japan
*
Email address for correspondence: okino.shinya.8n@kyoto-u.ac.jp

Abstract

Decaying turbulence in a density-stratified fluid with a Prandtl number up to $Pr=70$ is investigated by direct numerical simulation. In turbulent flow with a Prandtl number larger than unity, it is well known that the passive scalar fluctuations cascade to scales smaller than the Kolmogorov scale, and show the $k^{-1}$ spectrum in the viscous–convective range, down to the Batchelor scale. In decaying stratified turbulence, the same phenomenon is initially observed for the buoyant scalar of high $Pr~(=70)$, until the Ozmidov scale becomes small and the buoyancy becomes effective even at the Kolmogorov scale. After that moment, however, the velocity components near the Kolmogorov scale begin to show strong anisotropy dominated by the vertically sheared horizontal flow, which reduces the vertical scale of density fluctuations. An analysis similar to that of Batchelor (J. Fluid Mech., vol. 5, 1959, pp. 113–133) indeed shows that the vertically sheared horizontal flow reduces the vertical scale of density fluctuations, without changing the horizontal scale.

Type
JFM Papers
Copyright
© 2019 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

Barry, M. E., Ivey, G. N., Winters, K. B. & Imberger, J. 2001 Measurements of diapycnal diffusivities in stratified fluids. J. Fluid Mech. 442, 267291.Google Scholar
Bartello, P. & Tobias, S. M. 2013 Sensitivity of stratified turbulence to the buoyancy Reynolds number. J. Fluid Mech. 725, 122.Google Scholar
Batchelor, G. K. 1959 Small-scale variation of convected quantities like temperature in turbulent fluid. J. Fluid Mech. 5, 113133.Google Scholar
Bogucki, D., Domaradzki, J. A. & Yeung, P. K. 1997 Direct numerical simulations of passive scalars with Pr > 1 advected by turbulent flow. J. Fluid Mech. 343, 111130.+1+advected+by+turbulent+flow.+J.+Fluid+Mech.+343,+111–130.>Google Scholar
Brethouwer, G., Billant, P., Lindborg, E. & Chomaz, J. M. 2007 Scaling analysis and simulation of strongly stratified turbulent flows. J. Fluid Mech. 585, 343368.Google Scholar
de Bruyn Kops, S. M. 2015 Classical scaling and intermittency in strongly stratified Boussinesq turbulence. J. Fluid Mech. 775, 436463.Google Scholar
Dougherty, J. P. 1961 The anisotropy of turbulence at the meteor level. J. Atmos. Terr. Phys. 21, 210213.Google Scholar
Fincham, A. M., Maxworthy, T. & Spedding, G. R. 1996 Energy dissipation and vortex structure in freely decaying, stratified grid turbulence. Dyn. Atmos. Oceans 23, 155169.Google Scholar
Gargett, A. E. & Holloway, G. 1992 Sensitivity of the GFDL ocean model to different diffusivities for heat and salt. J. Phys. Oceanogr. 22, 11581177.Google Scholar
Gargett, A. E., Merryfield, W. J. & Holloway, G. 2003 Direct numerical simulation of differential scalar diffusion in three-dimensional stratified turbulence. J. Phys. Oceanogr. 33, 17581782.Google Scholar
Gerz, T. & Yamazaki, H. 1993 Direct numerical simulation of buoyancy-driven turbulence in stably stratified fluid. J. Fluid Mech. 249, 415440.Google Scholar
Gibson, C. H. & Schwarz, W. H. 1963 The universal equilibrium spectra of turbulent velocity and scalar fields. J. Fluid Mech. 16, 365384.Google Scholar
Girimaji, S. S. & Pope, S. B. 1990 Material-element deformation in isotropic turbulence. J. Fluid Mech. 220, 427458.Google Scholar
Godeferd, F. S. & Staquet, C. 2003 Statistical modelling and direct numerical simulations of decaying stably stratified turbulence. Part 2. Large-scale and small-scale anisotropy. J. Fluid Mech. 486, 115159.Google Scholar
Grant, H. L., Hughes, B. A., Vogel, W. M. & Moilliet, A. 1968 The spectrum of temperature fluctuations in turbulent flow. J. Fluid Mech. 34, 423442.Google Scholar
Hanazaki, H. & Hunt, J. C. R. 1996 Linear processes in unsteady stably stratified turbulence. J. Fluid Mech. 318, 303337.Google Scholar
Hanazaki, H. & Hunt, J. C. R. 2004 Structure of unsteady stably stratified turbulence with mean shear. J. Fluid Mech. 507, 142.Google Scholar
Hebert, D. A. & de Bruyn Kops, S. M. 2006 Relationship between vertical shear rate and kinetic energy dissipation rate in stably stratified flows. Geophys. Res. Lett. 33, L06602.Google Scholar
Itsweire, E. C., Helland, K. N. & Van Atta, C. W. 1986 The evolution of grid-generated turbulence in a stably stratified fluid. J. Fluid Mech. 162, 299338.Google Scholar
Kimura, Y. & Herring, J. R. 1996 Diffusion in stably stratified turbulence. J. Fluid Mech. 328, 253269.Google Scholar
Komori, S. & Nagata, K. 1996 Effects of molecular diffusivities on counter-gradient scalar and momentum transfer in strongly stable stratification. J. Fluid Mech. 326, 205237.Google Scholar
Kraichnan, R. H. 1968 Small-scale structure of a scalar field convected by turbulence. Phys. Fluids 11, 945953.Google Scholar
Lienhard, J. H. & Van Atta, C. W. 1990 The decay of turbulence in thermally stratified flow. J. Fluid Mech. 190, 57112.Google Scholar
Lin, J. T. & Pao, Y. H. 1979 Wakes in stratified fluids. Annu. Rev. Fluid Mech. 11, 317338.Google Scholar
Lindborg, E. 2006 The energy cascade in a strongly stratified fluid. J. Fluid Mech. 550, 207242.Google Scholar
Maffioli, A. 2017 Vertical spectra of stratified turbulence at large horizontal scales. Phys. Rev. Fluids 2, 104802.Google Scholar
Maffioli, A., Brethouwer, G. & Lindborg, E. 2016 Mixing efficiency in stratified turbulence. J. Fluid Mech. 794, R3.Google Scholar
Maffioli, A. & Davidson, P. A. 2016 Dynamics of stratified turbulence decaying from a high buoyancy Reynolds number. J. Fluid Mech. 786, 210233.Google Scholar
Majda, A. J. & Grote, M. J. 1997 Model dynamics and vertical collapse in decaying strongly stratified flows. Phys. Fluids 9, 29322940.Google Scholar
Métais, O. & Herring, J. R. 1989 Numerical simulations of freely evolving turbulence in stably stratified fluids. J. Fluid Mech. 202, 117148.Google Scholar
Orszag, S. A. & Patterson, G. S. 1972 Numerical simulation of three-dimensional homogeneous isotropic turbulence. Phys. Rev. Lett. 28, 7679.Google Scholar
Ozmidov, R. V. 1965 On the turbulent exchange in a stably stratified ocean. Izv. Atmos. Ocean Phys. 1, 493497.Google Scholar
Pao, Y. H. 1973 Measurements of internal waves and turbulence in two-dimensional stratified shear flows. Boundary-Layer Meteorol. 5, 177193.Google Scholar
Praud, O., Fincham, A. M. & Sommeria, J. 2005 Decaying grid turbulence in a strongly stratified fluid. J. Fluid Mech. 522, 133.Google Scholar
Riley, J. J. & de Bruyn Kops, S. M. 2003 Dynamics of turbulence strongly influenced by buoyancy. Phys. Fluids 15, 20472059.Google Scholar
Riley, J. J., Metcalfe, R. W. & Weissman, M. A. 1981 Direct numerical simulations of homogeneous turbulence in density-stratified fluids. In Proceedings of AIP Conference on Nonlinear Properties of Internal Waves (ed. West, B. J.), pp. 79112. American Institute of Physics.Google Scholar
Rogallo, R. S.1977 An ILLIAC program for the numerical simulation of homogeneous incompressible turbulence, NASA TM-73203.Google Scholar
Salehipour, H. & Peltier, W. R. 2015 Diapycnal diffusivity, turbulent Prandtl number and mixing efficiency in Boussinesq stratified turbulence. J. Fluid Mech. 775, 464500.Google Scholar
Salehipour, H., Peltier, W. R. & Mashayek, A. 2015 Turbulent diapycnal mixing in stratified shear flows: the influence of Prandtl number on mixing efficiency and transition at high Reynolds number. J. Fluid Mech. 773, 178223.Google Scholar
Smith, L. M. & Waleffe, F. 2002 Generation of slow large scales in forced rotating stratified turbulence. J. Fluid Mech. 451, 145168.Google Scholar
Smyth, W. D. 1999 Dissipation-range geometry and scalar spectra in sheared stratified turbulence. J. Fluid Mech. 401, 209242.Google Scholar
Staquet, C. & Godeferd, F. S. 1998 Statistical modelling and direct numerical simulations of decaying stably stratified turbulence. Part 1. Flow energetics. J. Fluid Mech. 360, 295340.Google Scholar
Stillinger, D. C., Helland, K. N. & Van Atta, C. W. 1983 Experiments on the transition of homogeneous turbulence to internal waves in a stratified fluid. J. Fluid Mech. 131, 91122.Google Scholar
Taylor, G. I. 1935 Statistical theory of turbulence. Proc. R. Soc. Lond. A 151, 421478.Google Scholar
Townsend, A. A. 1976 The Structure of Turbulent Shear Flow. Cambridge University Press.Google Scholar
Webster, C. A. G. 1964 An experimental study of turbulence in a density-stratified shear flow. J. Fluid Mech. 19, 221245.Google Scholar
Yeung, P. K., Xu, S., Donzis, D. A. & Sreenivasan, K. R. 2004 Simulations of three-dimensional turbulent mixing for Schmidt numbers of the order 1000. Flow Turbul. Combust. 72, 333347.Google Scholar
Yeung, P. K., Xu, S. & Sreenivasan, K. R. 2002 Schmidt number effects on turbulent transport with uniform mean scalar gradient. Phys. Fluids 14, 41784191.Google Scholar