Understanding Coriolis effects in centrifuge modeling of high-speed dry granular flows

Geotechnical centrifuge modeling provides an effective approach to reproduce prototype-relevant stress states for high-speed dry granular flows. Yet, in a rotating reference frame, the Coriolis acceleration induced by rapid granular motion can become comparable to the centrifugal acceleration, thereby markedly modifying run-out behavior and impact responses and complicating the interpretation of physical modeling results. This study integrates a suite of centrifuge model tests with discrete element method (DEM) simulations to systematically elucidate how Coriolis effects govern both the mobility of dry granular flows and their impact on rigid barriers. For run-out processes, a DEM framework incorporating both centrifugal and Coriolis accelerations is employed to compare granular mobility under three Coriolis configurations: dilative, compressive, and deflective conditions. The results indicate that the dilative Coriolis condition substantially enhances flow mobility and kinetic energy, whereas the compressive condition suppresses run-out and promotes flow densification. In contrast, under the deflective Coriolis condition, the sensitivity of the final run-out distance and overall flow scale to Coriolis effects is significantly reduced. This reduced sensitivity is attributed to two opposing deflection stages during propagation and deposition, suggesting a practical advantage for mitigating Coriolis-induced bias in centrifuge modeling. For impact processes, centrifuge experiments combined with DEM simulations are used to characterize granular impact behaviors on rigid barriers under different Coriolis conditions. The Coriolis effect has a limited influence on the peak magnitude of the total impact force, but it significantly alters the force time history and spatial distribution by modifying the velocity structure, flow thickness, and particle-scale momentum transfer. Notably, impact responses obtained under the dilative Coriolis condition are closer in force level to Coriolis-free reference cases, whereas the resultant force application point is comparatively insensitive to the Coriolis configuration. Overall, the results demonstrate that Coriolis effects should not be treated as a uniform experimental disturbance. Instead, they represent a key control factor whose influence depends on the specific quantities of interest. The findings provide methodological guidance for configuring centrifuge experiments and interpreting results in the modeling of high-speed dry granular flows, with explicit implications for both run-out and impact simulations.