Wave-resolving simulations of viscous wave attenuation effects on Langmuir circulation

Interaction processes of attenuating surface waves and underlying currents are explicitly simulated with a nonhydrostatic free surface numerical model. The model, designed with special attention to the numerical conservation properties of energy and momentum, is capable of accurately capturing the effect of the virtual wave stress, a viscous momentum transfer from waves to current. Simple experiments with the present model show that the Langmuir circulations in the wave-resolving simulations tend to be stronger than the ones in the Craik–Leibovich equation with corresponding Stokes drift profiles. The underestimation in the Craik–Leibovich equation can be corrected by addressing momentum transfer from attenuating waves to currents as the virtual wave stress at the surface.