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Centrifuge modelling of granular flows immersed in a viscous fluid: flow characteristics and impact forces

Natural hazards involving a combined action of granular debris and muddy floods are among the most common and dangerous phenomena in mountainous regions. The complex interactions developed between the debris and the surrounding fluid, have encouraged in the last three decades experimental and numerical research in different fields of the scientific community. While the development and understanding of dry granular flows in experimental conditions is following an understandable path, the case of immersed granular flows remains limited by the scaling considerations of the system.

In the current research, experiments over an arrangement of monodisperce particles immersed in a viscous fluid are performed in a geotechnical centrifuge. The developed model allows the simulation of free surface granular flows immersed in a viscous fluid, flowing down an incline in increased gravity conditions. Flow heights and velocity, basal fluid and total pressure, and impact forces are measured for a range of channel inclinations, bead sizes, fluid densities and fluid viscosities.

Obtained results confirm the simulation of large scale flows dynamics in a controlled scaled model. The scaling of the obtained interactions is helpful for further comparisons with numerical models and brings valuable information for the design of mitigation structures in natural hazards control systems.

Author(s):

Miguel Angel Cabrera    
University of Natural Resources and Life Sciences - Institute of Geotechnical Engineering
Austria

Wei Wu    
University of Natural Resources and Life Sciences - Institute of Geotechnical Engineering
Austria