Keywords: aerosols, aircraft wake, microphysics models, large–eddy simulation, LES, contrails, plume aerosol modelling, fluid trajectories, Airbus 340, water vapour deposition, soot cores, ice particles, aerosol size distribution, mixing
Numerical simulation of aerosols in an aircraft wake using a 3D LES solver and a detailed microphysical model
The global impact of aviation on the atmosphere is generally determined using the total amount of gas and particulate matter emitted at the aircraft engine exit but generally ignore some of the physical transformations occurring at much smaller scales in the aircraft wake. In this work, we present an offline alternative method based on the use of a detailed plume aerosol model combined to fluid trajectories calculated from 3D large–eddy simulations (LESs). The study has been limited to the first 10 s behind a type Airbus 340 aircraft. The results have been compared to those obtained from a one–way coupling approach including a simple microphysics water vapour deposition model on soot cores. The respective evolutions of average ice particles radius are in good agreement. Furthermore, different types of aerosol properties are examined including the charged volatile particles, the dry and activated soot and the ice crystals from homogeneous and heterogeneous freezing. The variability of the aerosol size distribution clearly illustrates the influence of the mixing, as a function of the position in the aircraft plume. Finally, the volatile particles distribution exhibits a bimodal shape resulting from the presence of charges, in agreement with that observed experimentally.