The effect of phase transitions on the droplet size distribution in homogeneous isotropic turbulence

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Abstract

We investigate the dynamics of an ensemble of discrete aerosol droplets in a homogeneous, isotropic turbulent flow. Our focus is on the stationary distribution of droplet sizes that develops as a result of evaporation and condensation effects. For this purpose we simulate turbulence in a domain with periodic boundary conditions using pseudo-spectral discretization. We solve in addition equations for the temperature and for a scalar field, which represents the background humidity against which the size of the droplets evolves. We apply large-scale forcing of the velocity field to reach a statistically steady state. The droplets are transported by the turbulent field while exchanging heat and mass with the evolving temperature and humidity fields. In this Euler-Lagrange framework, we assume the droplets volume fraction to be sufficiently low to allow one-way coupling of the droplets and turbulence dynamics. The motion of the droplets is time-accurately tracked. The Stokes drag force is included in the equation of motion of the individual droplets. The responsiveness of the droplets to small turbulent scales is directly related to the size of the individual spherical droplets. We perform direct numerical simulation to ultimately obtain the probability density function of the evolving radius of the droplets at different points in time with characteristic heat and mass transfer parameters. We determine the gradual convergence of the distribution function to its statistically stationary state for forced homogeneous, isotropic turbulence.
Original languageEnglish
Title of host publicationProceedings of the 5th European Conference on Computational Fluid Dynamics, ECCOMAS CFD 2010
EditorsA. Sequeira J.C.F. Pereira, J.M. Pereira
Pages1-10
Publication statusPublished - 2010
Event5th European Conference on Computational Fluid Dynamics (ECCOMAS CFD 2010) - Lisbon, Portugal
Duration: 14 Jun 201017 Jun 2010
Conference number: 5
http://www.eccomas-cfd2010.org/

Conference

Conference5th European Conference on Computational Fluid Dynamics (ECCOMAS CFD 2010)
Abbreviated titleECCOMAS CFD 2010
CountryPortugal
CityLisbon
Period14/06/1017/06/10
Internet address

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