Waveform behaviour in pressure varying debris flow models

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