Mercredi 17 juillet à 11h00, salle 250, bâtiment Fermi / IUSTI
Debris flows moving over loose beds change by gaining or losing particles through their base as stress and velocity vary within the sheared layer. Additionally, side boundary erosion significantly influences the entrainment process. This study introduces a comprehensive depth-averaged theory for dry erosive flows in a non-uniform channel, utilizing balance equations for mass, momentum, and kinetic energy. We assume a linearized $\mu(I)$ rheology for granular deformation and Coulomb friction along the sidewalls. The theory forecasts the kinematic behavior of channelized flows under various conditions, which we validate through two experimental setups: (1) a linear chute with abrupt tilt changes driving unsteady uniform flows; (2) a rotating drum to examine steady non-uniform flow. To explore the potential for wall erosion, we scale up the granular stress by conducting experiments under enhanced gravity conditions in a geotechnical centrifuge. Incorporating Coriolis force allows the model to address behavior under centrifuge-induced enhanced gravity. We develop an erosion model based on kinetic energy exchanges, informed by theoretical and experimental observations. The proposed erosion model is applicable to local erosion patterns and global erosion rates.