Large-eddy simulations of droplet impingement on rough iced airfoils

Ice accretion on aircraft surfaces poses significant challenges to flight safety and performance. Accurately predicting ice growth begins with determining the rate at which supercooled droplets impinge on aerodynamic surfaces. In this work, we present calculations of droplet impinging rates using large-eddy simulations (LES) of supercooled droplets using a Lagrangian particle-tracking approach. One-way coupling is employed in the simulations to account for the dilute nature of supercooled clouds. Simulated impingement rates are compared against experimental measurements for both NACA 23012 and NACA 0012 swept wing configurations to validate the model. The validated approach is then applied to a laser-scanned iced airfoil featuring pronounced surface roughness. We systematically investigate the influence of surface roughness and droplet Stokes number on local impingement patterns, providing insights into the role of roughness in the evolution of ice accretion. Our results contribute to a better understanding of particle-surface interactions in the context of aircraft icing and may inform future ice accretion modeling and mitigation strategies.