Chemically reactive dispersion into atmospheric boundary layers.

AGUIRRE C. A., S. SIMOËNS AND M. AYRAULT

Prato

Workshop; International Workshop on Physical Modelling of Flow and Dispersion Phenomena.; 2003

Firenze University

The objective of the present work is to apply a complete modelling taking into account for large turbulent scales, inertial turbulent scales and micro mixing for dispersion of species chemically reactant. For this a Large Eddy Simulation, continuous Lagrangian stochastic modeling and coalescence dispersion modeling are combined for the environmental study. The Large Eddy Simulation is necessary to take into account for large scales which modify the well established Kolmogoroff cascade. The turbulent mixing for the scales corresponding to the inertial zone of the Kolmogoroff cascade is approximated by a classic one particle and one time scale lagrangian stochastic model satisfying the well-mixed condition and the molecular diffusion by a deterministic and continuous in time pairing particle exchange model which is an extension of the coalescence-dispersion (CD) model of Curl, 1963. This model enables to reach many statistical quantities to be predicted. In this paper we present the effectiveness of the model to predict a second order rapid chemical reaction between two species. A fictive experiment of a reactive plume in a reference atmospheric boundary layer case is simulated. A point source of nitrogen monoxide NO is dispersed inside a boundary layer containing ozone O3 dispersed homogeneously. Dynamical and concentration statistical results display good agreement with experimental data. Chemical reaction produce realistic data.