Simulation of a contrail formation and early life cycle for a realistic airliner geometry

Abstract. Contrails—ice clouds that form in aircraft wakes—are thought to have a radiative impact up to twice that of CO2 emissions, although this estimate remains debated due to significant uncertainties. These uncertainties underline the need for further research into the entire life cycle of contrails, from the formation of initial ice crystals to their potential evolution into persistent cirrus clouds. The challenge lies in the wide range of spatial and temporal scales involved in contrail development.

This work presents a novel numerical methodology for simulating contrails from the onset of ice crystal formation to the dissipation of wingtip vortices. Unlike conventional methods that rely on analytical initialization, our approach couples Reynolds-averaged Navier–Stokes (RANS) with Large Eddy Simulation (LES) and synthetic turbulence techniques. This allows for a more accurate capture of near-field effects and a detailed consideration of how aircraft geometry influences the aerodynamic wake and subsequent contrail evolution.

Applied to a realistic aircraft under standard atmospheric conditions, our methodology revealed that horizontal tailplane vortices can trigger short-wavelength instabilities in wingtip vortices, significantly modifying the structure of the secondary wake. Comparisons with classical approaches show that the contrails generated by this work methodology are wider and more opaque, indicating a potentially greater warming effect.