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

Abstract. Contrails – ice clouds forming in aircraft wakes – may have a radiative impact up to twice that of CO2 emissions from aviation, though significant uncertainties remain. Understanding the entire contrail life cycle, from initial ice crystal formation to potential evolution into persistent cirrus clouds, requires addressing the wide range of spatial and temporal scales involved. This work presents a novel numerical methodology for simulating contrails from ice crystal formation onset to wingtip vortex dissipation. Unlike conventional methods relying on analytical initialization using Lamb-Oseen vortex pairs, our approach couples Reynolds-averaged Navier–Stokes (RANS) with Large Eddy Simulation (LES) and synthetic turbulence techniques. This enables more accurate capture of near-field effects and detailed consideration of how aircraft geometry influences aerodynamic wake and contrail evolution. Applied to realistic aircraft geometry under standard atmospheric conditions, our methodology revealed that horizontal tailplane vortices trigger short-wavelength instabilities in the main wingtip vortices, significantly modifying secondary wake structure. Compared to conventional methods, contrails generated through our methodology are wider with larger cross-sectional areas in the first few minutes following ice crystals formation. Previous studies showed contrail spatial dimensions significantly affect contrail-cirrus properties; for instance, under identical initial ice crystal number and mass, an A380 contrail-cirrus exhibits 20 % greater total extinction than a CRJ200 due to different contrail sizes. We propose a modified conventional method incorporating a quadripolar wake – two main wingtip vortices plus two secondary horizontal tailplane vortices – that more closely matches our methodology's simulations, which more precisely account for near-field aerodynamic effects.