Waveform behaviour in pressure varying debris flow models

Debris flows are composed primarily of densely packedparticles of rock, surrounded by water. Excess pressure (that is greaterthan hydrostatic) in the water decreases the stress supported thegranular matrix, and correspondingly reduces the overall frictionalresistance of the debris flow, allowing for larger velocities. Waves inthese flows can increase their run-out by creating deeper fronts of highfluid concentration and high fluid pressure. Continuum models of debrisflows have been refined with the inclusion of variation in excess fluidpressure. In this talk we will aim to examine the mechanisms in thismodel by studying the idealised case of flow on an inclined plane. Wewill solve for periodic waveforms to show the impact of varying fluidpressure throughout the wave, and examine unexpected behaviour withinthe model.