Publication Date

8-2015

Date of Final Oral Examination (Defense)

6-29-2015

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Mechanical Engineering

Department

Mechanical and Biomechanical Engineering

Supervisory Committee Chair

Inanc Senocak, Ph.D.

Supervisory Committee Member

Andrew Slaughter, Ph.D.

Supervisory Committee Member

Donna Calhoun, Ph.D.

Abstract

Understanding the way snow changes during environmental events has wide spread benefits ranging from avalanche prediction to water conservation. Snow on a micro-structural level constantly changes from the moment it forms. Snow metamorphosis is driven by the transport of water vapor. Thus far it has only been investigated as a pure diffusion process in dry snow, despite observations that suggest that natural convection may have a role in the heat and mass transport in snow packs. This thesis research numerically explores the role of transport processes in the context of snow metamorphism. An existing solidification model is reformulated to simulate the effects of natural convection on the evolution of snow micro-structure. The finite-element based Multi-physics Object Oriented Simulation Environment (MOOSE) is adopted for numerical computations. The solidification model is based on the phase field equation which captures an evolving interface without a direct interface tracking method. This equation is coupled with the Navier-Stokes equations to simulate fluid flow over complex solid boundaries, formed from micro-tomographic images of snow micro-structure. The numerical framework is then applied to investigate the role of diffusion and convection on the snow micro-structure. The results demonstrate diffusion based metamorphism on real snow. And natural convection is shown to develop in snow micro-structure under realistic conditions prior to coupling with phase change effects.

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