Advertisement

Numerical simulations of particle dispersion in stratified flows

  • G. BrethouwerEmail author
  • E. Lindborg
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 132)

Abstract

Several researchers have examined the vertical dispersion of fluid particles in stratified flows to obtain a better understanding of mixing in geophysical flows. Pearson et al. [5] used a Langevin model to predict that the mean square of vertical fluid particle displacements reaches a plateau with \(\langle\delta z^{2}\rangle \sim \langle w^{2}\rangle/N^2\ {\rm at}\ t \sim N^{-1}\) in stationary stratified flows. Here, w is the vertical velocity fluctuation and N is the Brunt-Väisälä frequency. At long times, they predict that \(\langle\delta z^{2}\rangle \sim \langle w^{2} \rangle t/N\), when molecular diffusion alters the particle density. Venayagamoorthy and Stretch [6] examined the role of the changing particle density on vertical dispersion in DNS of decaying stratified turbulence and observed that after one eddy turnover time diabatic dispersion dominated. Van Aartrijk et al. [1] studied particle dispersion in DNS of stationary strat-ified turbulence and observed a plateau with \(\langle\delta z^{2}\rangle \sim \langle w^{2} \rangle N^2\ {\rm at}\ t \sim N^{-1}\). However, some of the DNS showed that \(\langle\delta z^{2}\rangle \sim t\) at long times caused by density changes of fluid particles by molecular diffusion.

Keywords

Turbulent Kinetic Energy Froude Number Fluid Particle Particle Dispersion Particle Displacement 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Aartrijk M. van, Clercx H.J.H. and Winters K.B. 2008 Single-particle, particle-pair, and multiparticle dispersion of fluid particles in forced stably stratified turbulence. Phys. Fluids 20, 025104CrossRefADSGoogle Scholar
  2. 2.
    Brethouwer, G., and Lindborg, E. 2009 Numerical study of vertical dispersion by stratified turbulence. J. Fluid Mech., in press.Google Scholar
  3. 3.
    Lindborg, E., and Brethouwer, G. 2007 Stratified turbulence forced in rotational and divergent modes. J. Fluid Mech. 586, 83–108.zbMATHCrossRefMathSciNetADSGoogle Scholar
  4. 4.
    Lindborg, E., and Brethouwer G. 2008 Vertical dispersion by stratified turbulence. J. Fluid Mech. 614, 303–314.zbMATHCrossRefMathSciNetADSGoogle Scholar
  5. 5.
    Pearson, H.J., Puttock, J.S., and Hunt, J.C.R. 1983 A statistical model of fluid-element motions and vertical diffusion in a homogeneous stratified turbulent flow. J. Fluid Mech. 129, 219–249.zbMATHCrossRefADSGoogle Scholar
  6. 6.
    Venayagamoorthy, S.K., and Stretch, D.D. 2006 Lagrangian mixing in decaying stably stratified turbulence. J. Fluid Mech. 564, 197–226.zbMATHCrossRefADSGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  1. 1.Linné Flow CentreKTH Mechanics, KTHStockholmSweden

Personalised recommendations