Numerical modelling of the snow flow characteristics surrounding Sanae IV Research Station, Antarctica

• Main Author: Beyers, Johannes Hendricus Meiring
• Other Authors: Harms, T. M., University of Stellenbosch. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
• Format: Thesis
• Language: English
• Published: Stellenbosch : University of Stellenbosch 2004
• Subjects: Snow > Fluid dynamics; Katabatic winds; Theses > Mechanical engineering; Dissertations > Mechanical engineering; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10019.1/15935

Thesis (PhD)--University of Stellenbosch, 2004. ENGLISH ABSTRACT:This work is concerned with the numerical simulation of the aeolian snow transportation process (drifting or wind blown snow) and especially the snow deposition and erosion phenomenon (snow drift). The research work is interested in modelling the atmospheric boundary layer wind flow and its associated snow drifting processes around threedimensional obstacles by means of computational fluid dynamics (CFD). A modelling method is required to predict and evaluate the snow drifting phenomenon surrounding the SANAE IV research station in Antarctica. This station is of an elevated design to ensure that wind blown snow may travel around the structure relatively undisturbed and without deposition near the structure. This design is partly successful but localised drifts are formed especially leeward of the interconnecting structures that join the main building sections together. The theoretical and numerical description to describe the turbulent transport of the two-phase mixture of air and snow particles is investigated. This theory is subsequently employed to describe the snow deposition and erosion process and two models are developed to determine the deposition flux onto the snow surface. These models presented and discussed are a threshold based approach and a conservative based approach. The first model is dependent on a threshold shear velocity to determine the onset of either erosion or deposition. The second model determines the deposition or erosion flux based on the conservation of the snow mass transport in the near surface control volume. A numerical scheme that evaluates the snow deposition flux at the surface and forces a temporal surface adaptation during the simulation is established and implemented in a commercial CFD software code by means of user subroutines. Various test cases for which observed snow drift data are available are numerically modelled to validate the snow drift schemes presented in this work. These tests include the wind ...