A viscous curvilinear model for turbulent wind-wave interaction. Part 1. Application to fast wave condition.

The problem of turbulent wind and wave interactions is challenging to model because of the complexities of the turbulence stress in the wind field.  However, inspired by the data of large-eddy simulation of airflow over water waves and through developing a linear analysis framework for the wave boundary layer, we discovered that under certain conditions the interactions between the turbulent wind and waves can be explained by a linear theory without pursuing turbulence stress models.  In this presentation, we report a study of one of such scenarios, wind over fast-propagating water waves.  It is found that the fast wave effects on the airflow can be fully explained by a viscous curvilinear model that we recently developed.  By further examining the split equations for the viscous curvilinear model, we elucidate in detail the physical mechanisms underlying the fast wave effects on the airflow and the wind-wave momentum exchange at the water surface.