PROPOSAL NO.: CTS-0500056 PRINCIPAL INVESTIGATOR: C. RUTLAND INSTITUTION: UNIVERSITY OF WISCONSIN-MADISON
Large eddy simulation (LES) in rotating flows has important applications in atmospheric modeling and rotating machinery. Traditional LES approaches are based on simple modeling concepts and often fail to capture important features of turbulence in rotating systems. System rotation adds dispersive-wave interactions that significantly alter the dynamics of the energy cascade, and can change the direction of energy transfer. The Dynamic Structure Model methodology to be employed offers several significant advantages over existing LES approaches including the fact that no turbulent viscosity is used so that energy transfer can occur in either direction according to the requirements of local conditions and an energy budget is enforced between the resolved scales and the subgrid scales. This grant supports an in-depth study of LES for homogeneous, rotating flows, both decaying and forced. The performance of the Dynamic Structure Model will be compared to that of alternate models based on the ideas of an eddy-viscosity, self-similarity and a forward energy cascade. This research program has potential broad impact on LES modeling for many applications with rotation, including swirling engine flows, geophysical and astrophysical flows, climate modeling, and rotating magneto-hydrodynamic flows (e.g., dynamos). Quantitatively accurate LES can be used to explore parameter ranges that are inaccessible to DNS, i.e. larger Reynolds numbers and smaller Rossby numbers. This work could therefore also lead to expanded and deeper understanding of the mechanisms for nonlinear two-dimensionalization and the formation of cyclones in rapidly rotating flows. One graduate student will be advised jointly by the PI's. The student will participate in the Delta Program in Teaching and Learning, run by the Center for the Integration of Research, Teaching and Learning (CIRTL) supported by NSF to develop teaching skills. A focused and coordinated program within the Engine Research Center (ERC) at UW-Madison exists to develop LES models for complex engineering flows, primarily internal combustion engines. This project will become part of this center's activities and benefit from its strong support
