March 10, 1997Journal of Fluid Mechanics
Langmuir turbulence in the ocean
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Implication
Large-eddy simulation analysis reveals enhanced vertical mixing and coherent cell dynamics in the oceanic boundary layer, highlighting wave-driven forces in upper-ocean transport.
Key Points
- To examine the turbulent structures and transport dynamics in the ocean surface planetary boundary layer driven by interactions between wind shear and surface gravity waves.
- Analyzed solutions from large-eddy simulations of phase-averaged equations for oceanic currents in the surface boundary layer under aligned wind and wave forcing.
- Incorporated wave-driven vortex forces, Coriolis forces, and tracer advection modulated by Lagrangian Stokes drift at a realistic turbulent Langmuir number of 0.3.
- Stokes drift significantly enhanced turbulent vertical fluxes of momentum and tracers, turbulent kinetic energy, dissipation rates, and vertical velocity skewness.
- Langmuir cells emerged as the primary coherent turbulent structures, exhibiting longitudinal vorticity, down-wind surface convergence zones, and interior divergence rotated roughly 45° to the right of the wind.
- Langmuir cells expanded in horizontal scale with increasing depth and formed irregular spatial patterns that underwent localized mergers at convergence Y-junctions.
Cite This Study
McWilliams et al. (1997) studied this question.