Revisiting the Sharp-Interface Method for Applications to Wind–Wave Interactions

Accurate prediction of wind-wave interactions is essential for reliable weather forecasting, ocean–atmosphere dynamics, and addressing the growing vulnerability of coastal regions. When the air–water interface is modeled with finite thickness, numerical artifacts can emerge due to the artificial smearing of the interface. These artifacts become more pronounced when the simulation resolves physical length scales, such as wave curvature and turbulence structures above the interface, that are comparable to the thickness of the interface. These artifacts can lead to significant inaccuracies, including underprediction of turbulence intensity and misrepresentation of momentum exchange across the interface.

In this study, we assess a sharp-interface approach based on the ghost fluid method for simulating wind–wave interactions within the incompressible flow regime. A series of canonical test cases and practical wind–wave configurations are used to benchmark the method against diffuse-interface approaches. The sharp-interface framework demonstrates superior performance in capturing wind-side shear layers, resolving turbulence generation, and accurately modeling momentum transfer at comparable grid resolutions.

Despite these advantages, the method entails specific challenges, particularly regarding accurate curvature estimation and sensitivity to mesh quality. These limitations are critically examined, providing insights to inform future developments and applications of accurate and efficient wind-wave simulations.