Előadó: Lévay Sára (University of Navarra - SZFI, Wigner FK)
Előadásának címe: Secondary flows in anisotropic granular matter
Dátum: 2026. május 19. kedd, 10 óra
Helyszín: 1-es épület tanácsterem
Összefoglaló:
While granular materials are frequently modeled as collections of spheres, most natural and industrial grains are inherently anisotropic. This shape anisotropy leads to macroscopic phenomena that defy standard granular rheology, such as the spontaneous formation of secondary flows and surface heaping observed in particles with high aspect ratios.
In this seminar, I will present a theoretical and numerical investigation into the origin of these complex flow patterns. Using discrete element method simulations of elongated particles, we move beyond uniform shear to examine the system's linear response to modulated flow perturbations. We demonstrate that shape anisotropy generates significant normal stress differences, which constitute the physical mechanism driving spontaneous transverse vortices. I will discuss how these vortex patterns can be predicted analytically and show that the flow structure can invert its direction depending on the confinement geometry. Finally, I will connect these fundamental results to heaping in split-bottom cells, demonstrating that accounting for particle-level anisotropy is essential for predicting three-dimensional flow complexity in granular media.
