High-Order Multi-Resolution Multi-Dynamics Modeling for FLEAT
Abstract
Project Summary / Abstract The presence of large gradients often renders the quantitative analysis of dynamical systems challenging, be the analysis theoretical, observational or computational. This is because large gradients commonly lead to strong nonlinearities and to coupling among state variables and parameters. The emphasis of the Flow Encountering Abrupt Topography (FLEAT) initiative is on the effects of large topographic gradients and complex subsurface geometry on major current systems. The FLEAT focus is on the currents and vertical structures of the low-latitude western Pacific, specifically in the west Mariana Ridge region. Our goal for FLEAT is to explain and quantify multiscale interactions at abrupt topography among flow systems, vortices, internal tides and slope currents, by using and developing high-order multi-dynamics hybridizable discontinuous Galerkin (HDG) schemes for accurate process studies and by using and improving downscaling and two-way nesting schemes for realistic simulations and dynamics analyses. In collaborations with the DRI team, we plan to explain and quantify multiscale interactions at abrupt topography. We will define and set-up a set of flow configurations that encounter abrupt topographic gradients, with or without subsurface features and islands. This will involve time and 2D and 3D-in-space studies. To complete these studies, we will further develop our HDG codes towards a high fidelity modeling system, capable of multi-dynamics simulations at highorder over multi-resolution meshes. We will simulate and study nonlinear dynamics with nonhydrostatic or hydrostatic dynamics turned on. We plan to emphasize the multiscale interactions among the regional features observed, including non-hydrostatic stirring and mixing. We intend to utilize modeling and measurement results to inspire the development of process-oriented dynamical models for these interactions. We also plan to utilize our modeling results during the field campaigns to guide the sea sampling towards key processes and interactions. For realistic simulations and dynamics analyses in complex geometries, we will refine and utilize our nested-grid boundary conditions and conservative multi-grid exchanges such that upscale and downscale effects of multiple dynamics are transferred accurately across the multi-resolution domains, including transfers to-and-from unstructured and structured grids. We also plan to utilize and further evaluate our semi-analytical optimization scheme for the estimation of circulation features in complex multiply-connected regions, generalizing the “Island Rule”. We will improve our generalized vertical coordinate systems for primitive-equations (PEs) with a nonlinear free-surface, implementing model levels that optimally adapt to dynamics, for both our structured finite-volume and unstructured HDG codes. Finally, we plan to implement our HDG solver capability of separating the meshed domain between non-hydrostatic and hydrostatic elements, solving the element-local solutions accordingly and thus increasing efficiency. We will set-up and apply our MSEAS PE code for multi-resolution modeling of multiscale tidalto- mesoscale processes in the FLEAT regions. This involves two-way implicit nesting, parameter tuning, data assimilation, and data-model comparisons. We intend to explain and quantify processes involved when regional currents encounter the abrupt topography, subsurface features and island chains, with an emphasis on multiscale interactions. We will complete reanalyses with telescoping two-way nesting, to be used for dynamics analyses. For dynamics analyses, we plan to utilize term-by-term and flux balances, LCSs analyses, time and space variability decompositions, and new internal tide extraction equations that we developed.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512626
Entities
People
- Pierre Felix Lermusiaux
Organizations
- Massachusetts Institute of Technology
- Office of Naval Research
- United States Navy