Study of Turbulence Response to Wave Forcing using a Fast and Accurate Simulation Method

Surface waves play a crucial role in shaping Langmuir circulations and enhancing the turbulent mixing and transport in the upper-ocean boundary layer. Conventionally, the wave effect on the turbulence is modeled using the wave-phase-averaged approach. In this work, we introduce a wave-phase-resolved method for accurate and efficient simulations of turbulence under waves, directly coupling turbulence simulation with instantaneous wave orbital motions without the wave-phase averaging. We also introduce an approximate boundary condition, which allows us to formulate the turbulence simulation in a rigid-lid box domain while capturing the wave-phase effect. Using the proposed wave-phase-resolved method, we conduct simulations of a wind-shear-driven turbulence boundary layer interacting with a wave group. Our results show a significant increase in the turbulence intensity, particularly in the vertical fluctuations, after the wave group passes. This work elucidates how turbulence responds to the transient wave forcing in a wave group.