ABSTRACT
Lagrangian stochastic dispersion models (LSDM), also named Lagrangian particle models, are numerical models aimed at the simulation of the processes, being able to account for flow and turbulence space-time variations. In the LSDMs, the simplest and widely used boundary condition is the so-called perfect reflection: when a particle bumps against a boundary, it leaves the boundary in the opposite direction with the same vertical velocity and reversed sign. The straightforward method, even if time consuming, of computing the plume rise in the LSDM is based on the numerical integration, at each time step, of a set of differential equations expressing the conservation of the momentum flux, buoyancy flux, and volume flux. In most Lagrangian stochastic dispersion simulations, one has to account for the rise of buoyant plumes emitted by the industrial plants. The behavior of a chimney plume in the atmosphere is a rather complex process, which is influenced by emission characteristics, and actual wind, turbulence, and stratification profiles.
