Baroclinic Energy Conversion across Topographically Rough Straits with Application to Luzon Strait
CALIFORNIA UNIV SAN DIEGO LA JOLLA
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The long-term goal of this project is to assess the relative contribution of local dissipation versus far-field radiation of internal waves generated by the barotropic tide flowing across topographically rough straits in the Western Pacific. The specific objectives of the project are as follows 1 Perform large eddy simulation LES of a bottom boundary layer on rough topography to quantify near-bottom mixing as a function of slope angle, stratification strength, and other parameters and 2 Integrate the University of California at San Diego UCSD LES Model with the University of North Carolina UNC Ocean Model in a joint effort with A. Scotti to cover a realistic range of spatial and temporal processes deemed important to the near-field mixing observed in the field experiment. A non-hydrostatic model that numerically solves the unsteady, three-dimensional, primitive equations is used. Advanced models such as the dynamic mixed model and the dynamic eddy viscosity model are utilized to represent subgrid processes in the LES approach. A novel near-wall model has been developed so as to increase the Reynolds number of boundary flows to realistically large geophysical values. During the first year of the grant, significant effort was expended in advancing the capabilities of the numerical solver. This has allowed us to contrast the boundary layer among the cases of subcritical, critical, and supercritical slope. Three-dimensional, highly-resolved simulations of the bottom boundary layer under a barotropic tide on a slope have been performed. The difference between subcritical, critical, and supercritical slopes with respect to the mean velocity and the internal wave field has been highlighted. The impact of slope criticality on turbulence and dissipation rates will be obtained during the second year.
- Physical and Dynamic Oceanography
- Fluid Mechanics