Kinematics and scaling of granular flows within a centrifugal acceleration field

Physical modelling of debris flow has been instrumental for decades in enhancing our understanding of these processes. The geotechnical centrifuge plays a crucial role in this regard, enabling the creation of scaled models with stress fields closely resembling real-world scenarios. Despite its potential, the utilization of the geotechnical centrifuge is limited due to various challenges. Firstly, the technological complexity of designing and conducting experiments involving runout within the confined space of a centrifuge box poses a significant obstacle. Moreover, the interpretation of experimental results is hindered by the presence of apparent Coriolis acceleration, particularly for all kinematic processes. The Coriolis acceleration can potentially disrupt traditional scaling laws used for kinematic processes and lead to instability in simulated flows. Investigating this issue requires testing the same configuration on centrifuges of different radii, which is a formidable task.
In light of these challenges, this study proposes employing high-fidelity numerical simulations to examine the behaviour of an idealized granular flow in a centrifugal acceleration field. These simulations, based on the discrete element method, replicate an acceleration field analogous to that found within a geotechnical centrifuge. Unlike experimental setups, simulations are not constrained by technological limitations, allowing for the exploration of fully realized, steady-state flows under various conditions. The findings from the simulations indicate that traditional scaling can still be applicable, provided a sufficiently large centrifuge is utilized. However, in certain configurations, the Coriolis acceleration may induce instability, causing the flow to dilute, lose coherence, and disperse.