TY - JOUR
T1 - Concentration fluctuations and relative dispersion PDF
AU - Ferrero, E.
AU - Mortarini, L.
PY - 2005/4
Y1 - 2005/4
N2 - In this paper, we consider the problem of the relative dispersion of particle pairs released in a homogeneous isotropic stationary turbulent field. A one-dimensional two-particle Lagrangian stochastic model is considered. Two Langevin equations for the particles separation (Δ) and barycentre (Z) are presented and the results of the model simulations are discussed. The small-scale turbulence structure is analysed by reproducing the Δ and Z mean square trends. These are compared with the theoretical predictions and with a new formula to verify the Richardson's t3-law and the existence of an intermediate subrange, respectively, whose extension depends on the initial separation. Concerning the separation probability density function (PDF), two different forms are found for small and long times, respectively, according to the classical turbulence theory and the results of previous Lagrangian stochastic models. The mean concentrations and concentration fluctuations predicted by the model are compared with a new formula based on the Richardson separation PDF and with the formula based on the Gaussian PDF.
AB - In this paper, we consider the problem of the relative dispersion of particle pairs released in a homogeneous isotropic stationary turbulent field. A one-dimensional two-particle Lagrangian stochastic model is considered. Two Langevin equations for the particles separation (Δ) and barycentre (Z) are presented and the results of the model simulations are discussed. The small-scale turbulence structure is analysed by reproducing the Δ and Z mean square trends. These are compared with the theoretical predictions and with a new formula to verify the Richardson's t3-law and the existence of an intermediate subrange, respectively, whose extension depends on the initial separation. Concerning the separation probability density function (PDF), two different forms are found for small and long times, respectively, according to the classical turbulence theory and the results of previous Lagrangian stochastic models. The mean concentrations and concentration fluctuations predicted by the model are compared with a new formula based on the Richardson separation PDF and with the formula based on the Gaussian PDF.
KW - Concentration fluctuations
KW - Lagrangian stochastic model
KW - Relative dispersion
UR - http://www.scopus.com/inward/record.url?scp=16344378673&partnerID=8YFLogxK
U2 - 10.1016/j.atmosenv.2004.12.019
DO - 10.1016/j.atmosenv.2004.12.019
M3 - Article
SN - 1352-2310
VL - 39
SP - 2135
EP - 2143
JO - Atmospheric Environment
JF - Atmospheric Environment
IS - 11
ER -