Advances in Turbulence XII pp 51-55 | Cite as

# Numerical simulations of particle dispersion in stratified flows

## 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## Preview

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## References

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