Numerical simulation of two- and three-phase debris flow dynamics

• Antragstellerin: Dr. Nina Kirchner
• Fachliche Zuordnung: Mechanik
• Förderung: Förderung in 2003
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 5399825

Debris flows ("Murgänge" oder "Schlammlawinen" in german) are typical examples of saturated granular flows. A debris flow is a rapidly sheared gravity driven flow of a mixture of various sizes of sediment (from clay to boulders), water and air, down a moderately inclined slope, and is often occurring in mountainous regions after heavy rainfall. A striking phenomenon to be observed in debris flows is the effect of "inverse grading": during the avalanching motion of the debris flow, its individual particles are redistributed in such a way that large particles (e.g. boulders) gather on top and at the front of the flow, while small particles are concentrating toward the bottom and the rear. This segregation according to particle size is observed during the motion itself as well as in the deposits which are left behind. Starting from a thermodynamically consistent continuum mechanical mixture model (in which the so-called "principle of phase separation" has been partly abandoned to allow for interaction between various constituents on a constitutive level, and thus to allow for a redistribution of grains), the segregation effect will here be studied numerically for two-phase flows (e.g. rock avalanches) and three-phase flows (water-saturated debris flows).

• DFG-Verfahren: Sachbeihilfen