A Reynolds-averaged simulation of costal Langmuir cells in a constant depth and variable depth water column

Langmuir turbulence in the coastal ocean is driven by winds and waves and is characterized by Langmuir cells (LCs) that can span the full depth of the water column in unstratified settings. A solution strategy based on Reynolds averaging is introduced, relying on the coherency and persistence of full-depth LCs. Here these cells are resolved by the Reynolds-averaged formulation, treated as a secondary component to the wind and/or pressure gradient-driven primary flow. Two uniform depth simulations performed with the Reynolds-averaged formulation are submitted following the large-eddy simulation setup of Tejada-Martínez & Grosch (2007). Both cases are characterized by a turbulent Langmuir number (Lat) of 0.7 (see Tejada-Martinez and Grosch, 2007) and a wavelength of 6H and 3H (where H is the water column depth), parameters related to the wind and wave forcing conditions in the simulations. The case with the wavelength of 6*H and Lat = 0.7 corresponds to wind stress of 0.1 N/m^2, the significant wavelength of 90 m, and significant wave amplitude of 0.6 m measured in the field observations of full-depth Langmuir cells by Gargett & Wells (2007) in 15 meters depth. The variable depth simulation consists of a domain with depth varying between H=15 meters and H=7.5 meters over a 1 km distance along the x-direction. The depth is constant along the y-direction. The wind and waves are aligned in the y-direction. The wind stress, the wave amplitude, and the wavelength are fixed at 0.1 N/m^2, 0.6 m and 90 m (6*H = 6*15 m). The wave frequency is computed from the dispersion relation. The dataset consists of three-dimensional fields of velocity, turbulent kinetic energy, and epsilon values as a function of time for the uniform depth cases (160, 320, 480, and 640 minutes and 14 hours) and variable depth cases (1450, 290, 435, and 580 minutes). A detailed Readme document describes the model domain, forcing, and solution methods and provides snapshots of vertical velocity fluctuations.