The Open Atmospheric Science Journal

2014, 8 : 16-21
Published online 2014 December 12. DOI: 10.2174/1874282301408010016
Publisher ID: TOASCJ-8-16

Derivation of the Turbulent Time Scales and Velocity Variances from LES Spectral Data: Application in a Lagrangian Stochastic Dispersion Model

S. Maldaner , G. A. Degrazia , U. Rizza , S. B.A. Rolim , O. C. Acevedo , E. P. Marques Filho , L. P. Moor and D. R. Roberti
Universidade Federal de Santa Maria, Departamento de Física, Santa Maria, Brazil.

ABSTRACT

Turbulent time scales and velocity variances for a convective boundary layer are derived from large eddy simulation spectral data. Spectral peak frequencies obtained from LES data are used directly in expressions that allow establishing such times scales and velocity variances. These turbulent parameters were compared with those provided by experimental turbulence data. The comparison employing a stochastic dispersion model and observed concentration data shows that both parameterizations reproduce adequately the contaminant dispersion process in a convective boundary layer.

Keywords:

Convective boundary layer, Lagrangian dispersion model, LES spectral data, Local velocity decorrelation time scale, velocity variances.