Parallel, Large Eddy Simulation Code for Geophysical and Space Physical Applications

An effective simulation tool for the study of flows ranging from global earth or planetary circulations down to estuary scales and below is now feasible using massively parallel supercomputers. However, because of the wide range of scales and physical phenomena, no single code is likely to handle all problems. Here we propose to develop a systematic hierarchy of coupled codes that employ high-order efficient algorithms, state-of-the-art parallel computing software, and advanced turbulence modeling techniques. In Phase I, we shall develop an important building block of this integrated package, namely, a renormalization-group (RNG) large-eddy simulation (LES) code for flow simulations on scales of up to O(100) kilometers in the horizontal direction based on a robust high-order finite-difference algorithm for parallel supercomputers. In Phase II, this new code will be integrated with simulation tools for three-dimensional modeling of meso- and large-scale circulations. In particular, data obtained from simulations using the LES code will provide the necessary input for modeling of vertical mixing in the oceanic boundary layer to be used for global circulation modeling. A key feature of this work is the implementation of new advances in RNG modeling of geophysical and space physical flows that leads to high-order stabilization of negative viscosity phenomena important for global dynamics.