Large Eddy Simulation of the Early Jet-Vortex Interaction Phase of Contrails From Hydrogen Aircraft

Contrails have recently gained widespread attention, as their estimated warming potential is in the same order as aviation’s CO2 and is largely more uncertain. Our research is motivated by concerns about future hydrogen-fueled aircraft, as they will emit considerably more water vapor, albeit no soot. In this study, we compare the ice crystal number and net radiative forcing of contrails forming behind kerosene- and hydrogen-fueled aircraft with large-eddy simulations (LES) of the jet-vortex interaction phases of contrails. We simulate the jet-vortex interaction using prescribed axial and vortical velocity fields and employ Lagrangian particle tracking and microphysical models for ice crystal formation and growth. We find that hydrogen contrails have a fraction to half the number of ice crystals of kerosene contrails, except when the engine operates in the soot-poor regime and flies at lower altitudes. Higher atmospheric aerosol concentrations may also increase the net radiative forcing of contrails from hydrogen-fueled aircraft with respect to an equivalent kerosene-fueled aircraft.