Notes

Slide Show

Outline

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4	Casita disaster, Nicaragua
5	Model System – Dry Flow
6	TITAN 2D Simulation environment, currently for dry flow only Integrate GRASS GI data for topographical map High order numerical solver, adaptive mesh, parallel computing Extension to include erosion (Bursik)
7	Little Tahoma Peak, 1963 avalanche
8	Little Tahoma Peak, 1963 avalanche
9	Debris Flows Mass flows containing fluid ubiquitous and important Iverson (’97) 1D Mixture model; Iverson and Denlinger 2D mixture model and simulations How to model fluid/pore pressure motion?
10	2-Fluid Approach Model equations used in engineering literature Continuum balance laws of mass and momentum for interpenetrating solids and fluid Drag terms transfer momentum
11	2-Fluid Approach
12	2-Fluid Approach
13	Free boundary and basal surface
14	Scales Characteristic length scales (mm to km) e.g for Mount St. Helens (mudflow –1985) Runout distance » 31,000 m Descent height » 2,150 m Flow length(L) » 100-2,000 Flow thickness(H) » 1-10 m Mean diameter of sediment material 10^-3-10 m Scale: ε═H/L – several terms small and are dropped (data from Iverson 1995, Iverson & Denlinger 2001)
15	Model System-Depth Average Theory 2D to 1D Depth average solids conservation: where
16	Model System – 1D
17	Model System – 1D
18	Model System – 1D
19	Errors in modeling
20	Special Solutions
21	Special Solutions
22	Special Solutions
23	Special Solutions
24	Special Solutions
25	Time Evolution Mixed hyperbolic-parabolic system
26	Time Evolution
27	Time Evolution On inclined plane, volume fraction changes small special solution Interaction with ‘topography’ induces variation in φ
28	Modeling questions Evolution equation for fluid velocity? Efficient methods for computing 2D system including realistic topography
29	Comments on model