Analysis and Research on Energy Transfer from Wind to Waves Based on the SWAN Model

The mechanisms of energy transfer, storage, and dissipation at the ocean-atmosphere interface are crucial scientific issues in physical oceanography. In this paper, ten numerical experiments are systematically designed based on the SWAN ocean model to investigate the wind-to-wave energy transfer under constant wind field. The SWAN model employs its default wind stress drag coefficient to furnish the sea surface wind field across varying wind speeds, constructing a theoretically infinite-width and infinite-depth model, featuring free inflow and outflow boundaries for current and waves. In the numerical experiments, after the model reaches stability, wave energy experiences a rapid growth phase at wind speeds of 5-30 m/s. At around 10 m/s, corresponding to the wind speeds of monsoons and cold surges, the energy of the water column waves per unit area reaches 4.59x103 J (joules). At wind speeds of 3050 m/s, corresponding to typhoon-level wind speeds, the wave energy growth trend slows down. Finally, a parameterization scheme for the flux (WA) of atmospheric kinetic energy entering waves with respect to wind speed (U) under constant wind speeds is presented. This research has a substantial influence on atmospheric and oceanic circulation, and it is crucial for precise computation and practical prediction in numerical models.