237
9
Atmospheric Dispersion
with a Large-Eddy
Simulation: Eulerian and
Lagrangian Perspectives
Umberto Rizza, Giulia Gioia, Guglielmo Lacorata,
Cristina Mangia, and Gian Paolo Marra
CONTENTS
9.1 Introduction .................................................................................................. 238
9.2 Large-Eddy Simulation: The Moeng and Sullivan Model ........................... 239
9.2.1 Description ........................................................................................ 239
9.2.2 Numerical Scheme and Boundary Conditions ................................. 241
9.2.3 Lateral Boundary Conditions ........................................................... 242
9.2.4 Surface Boundary Conditions .......................................................... 242
9.2.5 Upper Boundary Conditions ............................................................. 243
9.3 Eulerian Dispersion with Large-Eddy Simulations and Experiments .......... 243
9.3.1 Eulerian Dispersion .......................................................................... 243
9.3.2 The Numerical Method.....................................................................244
9.3.3 Details of the LOD Method ..............................................................246
9.3.4 Boundary Conditions for the Advective Terms ................................248
9.3.5 Boundary Conditions for the Diffusion Terms .................................248
9.3.6 Dispersion Experiments ....................................................................248
9.3.6.1 Dispersion from Elevated Sources ..................................... 249
9.3.6.2 Dispersion from Near-Surface Sources Convective
Dispersion .......................................................................... 254
9.3.7 Conclusions for the Eulerian Experiments ....................................... 257
9.4 Lagrangian Dispersion with Large-Eddy Simulations and Experiments ..... 259
9.4.1 Lagrangian Dispersion ...................................................................... 259
9.4.2 Pair Dispersion in a LES-Generated Neutral PBL ........................... 259
9.4.2.1 The Simulated PBLs .......................................................... 259
9.4.2.2 Fixed-Scale Statistics ......................................................... 261
© 2010 by Taylor and Francis Group, LLC
9
Atmospheric Dispersion
with a Large-Eddy
Simulation: Eulerian and
Lagrangian Perspectives
Umberto Rizza, Giulia Gioia, Guglielmo Lacorata,
Cristina Mangia, and Gian Paolo Marra
CONTENTS
9.1 Introduction .................................................................................................. 238
9.2 Large-Eddy Simulation: The Moeng and Sullivan Model ........................... 239
9.2.1 Description ........................................................................................ 239
9.2.2 Numerical Scheme and Boundary Conditions ................................. 241
9.2.3 Lateral Boundary Conditions ........................................................... 242
9.2.4 Surface Boundary Conditions .......................................................... 242
9.2.5 Upper Boundary Conditions ............................................................. 243
9.3 Eulerian Dispersion with Large-Eddy Simulations and Experiments .......... 243
9.3.1 Eulerian Dispersion .......................................................................... 243
9.3.2 The Numerical Method.....................................................................244
9.3.3 Details of the LOD Method ..............................................................246
9.3.4 Boundary Conditions for the Advective Terms ................................248
9.3.5 Boundary Conditions for the Diffusion Terms .................................248
9.3.6 Dispersion Experiments ....................................................................248
9.3.6.1 Dispersion from Elevated Sources ..................................... 249
9.3.6.2 Dispersion from Near-Surface Sources Convective
Dispersion .......................................................................... 254
9.3.7 Conclusions for the Eulerian Experiments ....................................... 257
9.4 Lagrangian Dispersion with Large-Eddy Simulations and Experiments ..... 259
9.4.1 Lagrangian Dispersion ...................................................................... 259
9.4.2 Pair Dispersion in a LES-Generated Neutral PBL ........................... 259
9.4.2.1 The Simulated PBLs .......................................................... 259
9.4.2.2 Fixed-Scale Statistics ......................................................... 261
© 2010 by Taylor and Francis Group, LLC