´¡²ú²õ³Ù°ù²¹³¦³Ù:ÌýUnderstanding pollutant dispersion in atmospheric boundary layers is essential for assessing environmental and health risks from accidental or continuous emissions. Previous wind-tunnel experiments examined the influence of source size, elevation, and emission velocity on passive scalar dispersion in neutral boundary layers. These studies characterized concentration statistics, intermittency, and mixing, showing that concentration probability density functions (PDFs) are consistently well described by a Gamma distribution.
Building on this work, we investigate the effect of atmospheric stability using wind-tunnel experiments and Large-Eddy Simulations. Stable stratification suppresses turbulence, confines the plume, and modifies both large-scale meandering and small-scale mixing. Although concentration fluctuations and intermittency decrease with increasing stability, concentration PDFs remain accurately represented by a Gamma distribution. The combined experimental and numerical results show that stability suppresses both meandering and turbulent mixing, with a stronger impact on large-scale fluctuations.
Bio:Pietro Salizzoni holds a Bachelor degree in Environmental Engineering from Politecnico di Torino and a PhD in Environmental Fluid Mechanics. He is full Professor at École Centrale de Lyon. His teaching and research activities address physical phenomena associated with natural and technological risks, both accidental and persistent, with a focus on the dynamics of environmental flows. In particular, his studies deal with pollutant dispersion in the urban atmosphere, the propagation of hot smokes in free and confined environments, the ventilation of road tunnel in case of fire, the characterization of atmospheric dispersion of toxic and flammable substances, the transfer within the environment and food chain of dioxin and other persistent organic pollutants.