Resolvent analysis of turbulent flows over progressive surface waves

Understanding the mechanism of air-sea interaction is crucial for numerous geophysical, environmental, and engineering applications. In this study, a reduced-order model for the turbulent flows over progressive surface waves using resolvent decomposition is proposed. The model is based on the linearized Navier-Stokes equations with a boundary-fitted grid. Large-eddy simulations (LES) with various wave ages are performed to obtain the two-dimensional time-averaged flows. The resolvent analysis reveals the energy amplification and the associated coherent structural response to turbulent fluctuations over a wide range of frequencies. Using this method, we are able to examine the airflow responses under various wave conditions and describe the flow characteristics with a low-rank model.