Author(s): Denis Dartus; Moacyr Araujo; Philippe Maurel; Lucien Masbernat

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Abstract: The Craik-Leibovich equations including vortex forcing terms and a pressure gradient force in x-momentum are integrated numerically. Some typical environmental problems with strong longitudinal currents are analysed. Results are compared with Leibovich & Paolucci's stability analysis which allows to identify situations where Langmuir cells exist. An establishing characteristic time for the setting of cells has the same order of magnitude as in field observations. Its variation with Langmuir number (La) and nondimensional depth is pointed out. A scaling analysis of the momentum equations is made for vanishing La. Influence of the longitudinal current intensities over Langmuir circulations structure is showed and confirmed by numerical results : more energetic convective cells are verified for situations where stronger longitudinal velocities are present. Results indicate how the redistribution of the shear stress induced by secondary flows is important for mixing in the water column and for coastal sediment transport.

DOI: https://doi.org/10.1080/00221680009498349

Year: 2000