Spatial Simulation of Contrail Formation in Near-Field of Commercial Aircraft

Abstract

During this study, three-dimensional numerical simulations of contrails generated by commercial aircraft in cruise conditions were performed. The objective was to study the early development of contrails in the near field of an aircraft, including engine core and bypass flows. Computational fluid dynamics simulations, based on the three-dimensional Reynolds-averaged Navier–Stokes approach, were carried out on a realistic aircraft geometry. A microphysical model was implemented in the computational fluid dynamics code to simulate particle growth using an Eulerian approach. Results showed that the mixing processes in the bulk plume were in good agreement with the literature. Then, the early growth of a contrail in the near wake of the aircraft was investigated for two ambient relative-humidity conditions. This parameter played a significant role in contrail local properties. Increased relative humidity led to an increase in the fraction of particles under the supersaturated condition and condensation rate. This resulted in a higher mean particle radius and, as a consequence, in a higher optical depth, making contrails more distinct. Particle-size distribution shifted toward larger particles due to an increase in available vapor and got narrower as the relative humidity increased because more particles were in favorable conditions for ice growing.