PIV for Lagrangian Scale Evaluation in a Convective Boundary Layer
The Lagrangian description of the turbulence is the natural approach to the study of all the phenomena in which one want recognize the behaviour of the fluid particles during their motion within the field. A typical example of such phenomena is the pollutants dispersion in the Atmosphere, as the pollutant particles behave as tags of the fluid. The knowledge of the Lagrangian statistics gives a full description of the behaviour of a single particle since it was released from the source; this informations are very useful to calibrate the Lagrangian numerical models of dispersion, based on simulations of time histories of the pollutant particles released from a source (Thomson 1984). In the present experiment, the atmospheric Convective Boundary Layer (CBL), occurring in late morning and early afternoon of the sunny days above a uniform and plain terrain is simulated. Above this layer, a region in which the temperature grows with the height (the Capping Inversion), almost completely avoids the air-mass exchange between the CBL and the overlaying Free Atmosphere (Wyngaard 1985).
KeywordsConvection Stratification Polystyrene Velocimetry
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