Stripes in granular avalanches: how segregation couples with vortices

Pearse et al. ( J. Fluid Mech. vol. 1032, 2026, A4) reveal that a novel segregation pattern emerges when mixtures of large and small particles flow rapidly down a slope. Regular longitudinal stripes of large particles are observed, arising from the coupling between longitudinal vortices and vertical segregation processes. Pearse et al. derive a simple yet insightful model capturing the segregation dynamics.