Inertial effects in just-saturated axisymmetric column collapses

Abstract This work introduces a scaling analysis of sub-aerial axisymmetric column collapses glass beads and Newtonian glycerol-water solutions mimicking some the behaviours debris flows. The were in size range where their inertia partly decouples collapse behaviour from water column. Experiments explored viscous, surface tension particle effects through systematic variation fluid viscosity. Crucially geotechnical centrifuge was used to access elevated effective gravitational accelerations driving collapse, allowing field-scale viscous be replicated. Temporal pore pressure run out front position evolution data extracted using transducer high speed imaging, respectively. A least-squares fitted scale demonstrated that all characteristic dimensionless quantities acceleration phase could described as function column-scale Bond number $$\text{ Bo }$$ Bo , Capillary Ca Ca system $$r^*$$ r ∗ grain-fluid density ratio $$\rho ^*$$ ρ . characterised by positions controlled Bo}/\text{Ca}$$ / indicates grain-scale are negligible such inertial they may dominate laboratory-scale granular-fluid flow geometric similarity between grain is preserved. Graphical abstract