Turbulent Condensation of Droplets: Direct Simulation and a Stochastic Model
Open Access
- 1 March 2009
- journal article
- Published by American Meteorological Society in Journal of the Atmospheric Sciences
- Vol. 66 (3), 723-740
- https://doi.org/10.1175/2008jas2734.1
Abstract
The effect of turbulent mixing on droplet condensation is studied via direct numerical simulations of a population of droplets in a periodic box of homogeneous isotropic turbulence. Each droplet is tracked as a fluid particle whose radius grows by condensation of water vapor. Forcing of the small wavenumbers is used to sustain velocity, vapor, and temperature fluctuations. Temperature and vapor fluctuations lead to supersaturation fluctuations, which are responsible for broadening the droplet size distribution in qualitative agreement with in situ measurements. A model for the condensation of a population of cloud droplets in a homogeneous turbulent flow is presented. The model consists of a set of Langevin (stochastic) equations for the droplet area, supersaturation, and temperature surrounding the droplets. These equations yield corresponding ordinary differential equations for various moments and correlations. The statistics predicted by the model, for instance, the droplet area–supersaturation correlation, reproduce the simulations well.Keywords
This publication has 25 references indexed in Scilit:
- Observations of Small-Scale Turbulence and Energy Dissipation Rates in the Cloudy Boundary LayerJournal of the Atmospheric Sciences, 2006
- Contrail formation in aircraft wakesJournal of Fluid Mechanics, 2004
- Particle-turbulence interactions in atmospheric cloudsAnnual Review of Fluid Mechanics, 2002
- On the prediction of gas–solid flows with two-way coupling using large eddy simulationPhysics of Fluids, 2000
- Direct numerical simulation of turbulence modulation by particles in isotropic turbulenceJournal of Fluid Mechanics, 1998
- The effect of saturation fluctuations on droplet growthJournal of Aerosol Science, 1997
- An efficient tool for the study of 3D turbulent combustion phenomena on MPP computersPublished by Springer Science and Business Media LLC ,1995
- Compact finite difference schemes with spectral-like resolutionJournal of Computational Physics, 1992
- Turbulent Characteristics of Some Canadian Cumulus CloudsJournal of Applied Meteorology, 1977
- Simple Eulerian time correlation of full-and narrow-band velocity signals in grid-generated, ‘isotropic’ turbulenceJournal of Fluid Mechanics, 1971