A twofluid model for avalanche and debris flows
Abstract
Geophysical mass flows—debris flows, avalanches, landslides—can contain O(1061010)m3 or more of material, often a mixture of soil and rocks with a significant quantity of interstitial fluid. These flows can be tens of meters in depth and hundreds of meters in length. The range of scales and the rheology of this mixture presents significant modelling and computational challenges. This paper describes a depthaveraged ‘thin layer’ model of geophysical mass flows containing a mixture of solid material and fluid. The model is derived from a ‘twophase’ or ‘twofluid’ system of equations commonly used in engineering research. Phenomenological modelling and depth averaging combine to yield a tractable set of equations, a hyperbolic system that describes the motion of the two constituent phases. If the fluid inertia is small, a reduced model system that is easier to solve may be derived.
 Publication:

Philosophical Transactions of the Royal Society of London Series A
 Pub Date:
 July 2005
 DOI:
 10.1098/rsta.2005.1596
 Bibcode:
 2005RSPTA.363.1573P
 Keywords:

 avalanche flow;
 debris flow;
 mixture theory;
 twophase flows