Riassunto analitico
Clouds are central to meteorology as they regulate Earth's energy balance and drive vertical transport of heat and momentum, particularly through deep convection processes that influence planetary-scale circulation. However, accurately modeling clouds presents significant challenges due to their multiscale nature, sensitivity to initial and boundary conditions, and multiphase flow dynamics. This thesis investigates the self-aggregation of moist convection within a conditionally unstable environment by performing direct numerical simulations (DNS) of Rayleigh-Bénard convection at aspect ratios up to 64. To focus on fundamental buoyancy-driven mechanisms, the study adopts simplified thermodynamics for cloudy air coupled with the Boussinesq approximation. Results, compared with classical Rayleigh-Bénard convection, reveal pronounced vertical asymmetry and distinctive mixing behavior within clouds highlighted by performing conditioned statistics, emphasizing the unique dynamics of moist convection. Finally, the study evaluates the influence of numerical grid resolution.
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Abstract
Clouds are central to meteorology as they regulate Earth's energy balance and drive vertical transport of heat and momentum, particularly through deep convection processes that influence planetary-scale circulation. However, accurately modeling clouds presents significant challenges due to their multiscale nature, sensitivity to initial and boundary conditions, and multiphase flow dynamics. This thesis investigates the self-aggregation of moist convection within a conditionally unstable environment by performing direct numerical simulations (DNS) of Rayleigh-Bénard convection at aspect ratios up to 64. To focus on fundamental buoyancy-driven mechanisms, the study adopts simplified thermodynamics for cloudy air coupled with the Boussinesq approximation. Results, compared with classical Rayleigh-Bénard convection, reveal pronounced vertical asymmetry and distinctive mixing behavior within clouds highlighted by performing conditioned statistics, emphasizing the unique dynamics of moist convection. Finally, the study evaluates the influence of numerical grid resolution.
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