HPCCprojects:Simulation of Granular Flows

Simulation of Granular Flows

Project description

Granular flows are ubiquitous in the environment. In some cases interaction with the ambient fluid is critical, for example debris flows, turbidity currents and powder snow avalanches. In other cases the flow dynamics are governed only by the dry granular material, for example, rock-slides and dense avalanches. In both cases accurate theories are necessary for the describing the granular material, but there is no known governing equation for granular matter in the way that the Navier-Stokes equations describes fluids. The aim of this project is to study granular systems by direct simulation using the Discrete Element Method (also known as Molecular Dynamics), in which the equation of motion for each individual grain in integrated in time accounting for solid contacts and interactions with the ambient fluid.

Objectives

Direct simulation of washboard road and analysis of the forces, and flow field around a moving plough or wheel. Washboard road is a particularly simple surface instability that can be viewed as a simple model for many geomorphological patterns.

Direct simulation of granular flow in a drum. Rotating drums are one of the simplest granular experiments that can be performed and are very useful for categorising geophysical materials. The aim of this project is a detailed comparison between experiments and simulations focusing on the transition between steady and avalanching motio n .

Segregation in granular flows. The "Brazil Nut Effect" is where larger particles move towards a free surface in a moving granular system. This is important for understanding deposit patterns and can have a large effect on the dynamics of granular flows greatly increasing runout of rockslides for example. The aim of this project is to verify and develop improved theories of granular segregation.

Time-line

Work on all these project started in December 2011 and is ongoing

Models in use

A custom code written in Fortran 2007 is used for the simulations. Data processing is performed with MATLAB and visualisation with a custom C renderer.

Results

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Users

Jim McElwaine

• <name HPCCuser>

Funding

None

Links

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