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Item Accurate conservative simulations of multiphase flows applying the height function method to Rudman dual grids(Montana State University - Bozeman, College of Engineering, 2019) Olshefski, Kristopher Thomas; Chairperson, Graduate Committee: Mark OwkesGas-liquid flows can be significantly influenced by the surface tension force, which controls the shape of the interface. The surface tension force is directly proportional to the interface curvature and an accurate calculation of curvature is essential for predictive simulations of these flow types. Furthermore, methods that consistently and conservatively transport momentum, which is discontinuous at the gas-liquid interface, are necessary for robust and accurate simulations. Using a Rudman dual mesh, which discretizes density on a twice as fine mesh, provides consistent and conservative discretization of mass and momentum. The height function method is a common technique to compute an accurate curvature as it is straightforward to implement and provides a second-order calculation. When a dual grid is used, the standard height function method fails to capture fine grid interface perturbations and these perturbations can grow. When these growing perturbations are left uncorrected, they can result in nonphysical dynamics and eventual simulation failure. This work extends the standard height function method to include information from the Rudman dual mesh. The proposed method leverages a fine-grid height function method to compute the fine-gird interface perturbations and uses a fine-grid velocity field to oppose the fine-grid perturbations. This approach maintains consistent mass and momentum transport while also providing accurate interface transport that avoids non-physical dynamics. The method is tested using an oscillating droplet test case and compared to a standard height function. Various iterations of the fine grid method are presented and strengths and shortcomings of each are discussed.Item Modeling mass balance at Robertson Glacier, Alberta, Canada 1912-2012(Montana State University - Bozeman, College of Letters & Science, 2017) Scanlon, Ryan Scott; Chairperson, Graduate Committee: Mark L. Skidmore; Jordy Hendrikx (co-chair)Glacier mass balance is important to study due to the role of glaciers in the hydrological cycle. Glacier mass balance is typically difficult to measure without numerous in situ measurements and monitoring over the course of many years. Physically based melt models are a good tool for estimating melt using temperature, solar radiation, and albedo and are used extensively in this thesis. A Degree Day (DD) model and an Enhanced Temperature Index (ETI) model are used to model mass balance for Robertson Glacier, Alberta, Canada during the period 1912-2012. The DD model only incorporates temperature, while the ETI model incorporates temperature, incoming solar radiation, and albedo. Incoming solar radiation was modeled for the period 2007-2012 and parameterized for the period 1912-2006 while temperature was measured at the regional scale and synthesized for Robertson Glacier and the snowpack thickness was modeled using PRISM. The DD and ETI models both assume a static ice mass, i.e. no flow or change in ice elevation due to mass loss over the century time period. Both models estimate a high value of annual and accumulated mean mass loss for the period 1912-2012. Sensitivity analyses of model inputs indicate that snowpack is an important factor, and it appears PRISM estimates may underrepresent beginning of the year snowpack by 220% based on a comparison of modelled to measured values on the adjacent Haig Glacier. Avalanching is not a key component of accumulation on the Haig Glacier but is a key process at Robertson Glacier, and could result in locally doubling the snowpack accumulation in avalanche zones. These factors including the resultant albedo changes with a thicker snowpack are all part of a compounding negative feedback cycle on glacier mass loss. In summary, the thesis has highlighted several potential limitations to the ETI and DD models for assessing mass loss for a small mountain glacier in the southern Canadian Rockies and provides suggestions for future modelling work in this region.Item Desorption due to recoil induced by neutrino emission and auger relaxation of ³�Cl following the electron capture decay of ³�Ar(Montana State University - Bozeman, College of Letters & Science, 1995) Zhu, Lin