Seminar Tomás Trewhela “Shear-driven segregation in granular flows: a coupled Stokes’ problem”

Seminar “Shear-driven segregation in granular flows: a coupled Stokes’ problem”

Speaker:

Tomás Trewhela is Assistant Professor in the Faculty of Engineering and Sciences, Universidad Adolfo Ibañez (UAI). His research focuses on granular materials and their flow, with special interest in particle-size segregation, debris flows, sediment bedforms and bedload transport.

• Wednesday, May 24, 2023
• 4:15 pm
• English
• Sign up to receive link

Abstract:

From a bag of dried nuts to a debris flow, a granular bulk is segregated by their particles sizes when sheared. This relative particle motion caused by segregation alters the flow's rheology, creating a feedback by changing the very same segregation fluxes. Insofar segregation models have been physically parameterized, the study of this complex rheology-segregation feedback has become a possibility. For this seminar, I solve numerically the Stokes’ first problem for a granular mixture of differing particle sizes. In an unstable initial condition, i.e., small particles on top of large ones, the top plate movement rapidly transfers momentum to the granular bulk that reaches a transient solution for the velocity profile. At a large time scale, segregation fluxes redistribute particles within the bulk, hence altering the frictional response and the resulting velocity profile. Conclusions are drawn around the particles’ size and frictional ratios role on the resulting solutions and velocity profiles.

Sign up here: