Feasibility study for understanding ice cave microclimate through thermo-fluid dynamics approaches

Ice caves are classified as sporadic permafrost phenomena and consist of lava tubes or cave systems in which perennial ice forms. Ice within caves can be very old and can carry important information on permafrost conditions, climate changes and past climates. Until now, these systems have been investigated mainly with an experimental approach. A critical topic in ice cave studies is the understanding of how the internal environment interacts with the external and how these systems react to changes in the external conditions. In this thesis, a new numerical approach to understand ice cave microclimate is proposed. Numerical studies can contribute greatly to a better understanding of the processes involved in the formation and preservation of the ice in cave. Furthermore, computational fluid dynamic methods can be a valuable support to define new experimental setups and to interpret experimental results. The cave studied in this work is Leupa ice cave, located in Friuli Venezia Giulia region. Air flows inside Leupa ice caves were characterized with an integrated approach using both experimental and numerical methods. A general approach was initially adopted and three representative days were identified to investigate which circulation patterns can develop under different environmental conditions. The comparison of numerical and experimental data permitted to evaluate the quality of the simulations and to identify the main problematics that need to be investigated further. Deeper investigations were then performed for a single day to investigate the temperature and boundary conditions effect on the flow thermo-dynamics inside the cave. New insights on the fluid-dynamic behavior of Leupa ice cave are achieved, showing that numerical methods could represent a powerful tool to study ice caves, improving and integrating the information that could be obtained from standard experimental measurements.