Rolling Samaras Exhibit Aerodynamic Advantages Under Wind Perturbations

Rolling samaras rotate about both their spanwise and vertical axes during descent, but their aerodynamic responses to wind disturbances remains understudied. We investigate how three rolling species—F.americana, F.excelsior, and L.tulipifera—respond to concentrated crosswind disturbances compared to non-rolling maple (A.ginnala) samaras. High-speed motion tracking reveals that rolling samaras maintain coherent autorotation and achieve greater lateral drift and larger displacement ratios than non-rolling counterparts. Aerodynamic regimes are classified using a tip-speed-normalized crosswind velocity and a rolling-adjusted edge velocity that accounts for both autorotation and spanwise roll. A helical descent model incorporating crosswind-induced tilt predicts trajectory deformation and changes to drag relevant area. Dispersal efficacy is assessed through a dimensionless framework that compares experimental to simulated dispersal. Rolling samaras are pushed laterally greater distances than non-rolling samaras, which is relevant to plant ecology and the design of passively stable aerial systems.