Snow documentation

By Alsidqi Hasan

This development is supported by the French National Agency of Research (ANR), via the "Snow White" project (ANR-06-BLAN-0396-01).

Introduction

A novel Discrete Element Method (DEM) employing polyhedral elements based on experimental data is developed. It is implemented in an algorithm that simulates a dynamic model of creep deformation based on observed snow grains packing. The model uses a grain-scale algorithm that requires geometrical input parameters from a three-dimensional (3D) scans of the observed snow grains packing. The 3D high resolution image was obtained from scanning a cylindrical snow specimen using Synchrotron X-ray Diffraction Contrast Tomography (DCT) technique.

A scanned ice grains packing.

A reconstruction algorithm is used to convert tomography data into a set of grains, represented as a set of parallel layers. The orientation of layers correspond to crystallographic planes, and the layers can slide relative to each other according to a viscous creep law, thus simulating the deformation of mono-crystaline ice grains.

Geometry obtained after tomography (left), and polyhedral representation in Yade (right).