Thermodynamic Feedback of Sea Spray at Air-Sea Interface

Sea-spray droplets generated in large quantities under strong winds exchange heat and water vapor with the turbulent airflow, which potentially modifies air-sea heat fluxes. However, questions regarding the appropriate method for modeling the effects of spray on air-sea fluxes still exist due to untested assumptions in existing models and low fidelity in the measurements. In this study, an Eulerian-Langrangian model is implemented to simulate two-way coupled spray droplets in a turbulent flow via direct numerical simulations. While the study is not meant to replicate a real air-sea interface, the fundamental physics underlying turbulence-droplet coupling is the focus. With high-fidelity simulations with mono- and poly-dispersed droplet size distributions, the dissertation covers topics on: (1) the sensitivity of air-sea heat fluxes on various droplet and flow parameters; (2) fundamental assumptions on the microphysics and the poly-dispersity of spray droplets using bulk air-sea algorithms; and (3) potential improvements and corrections to the bulk algorithms on parameterizing spray effects. The findings of this dissertation bring insights on the spray microphysics and feedback effects from a small-scale perspective, which narrows the gap in understanding the spray effects at the air-sea interface for the large-scale modeling community.