Joe Oefelein
Professor, Aerospace Engineering, Georgia Institute of Technology
Friday, Mar. 18 | 12:00 P.M. | AERO 114
Abstract: This presentation will highlight recent progress and challenges in development of the Large Eddy Simulation (LES) methodology for treatment of turbulent reacting flow processes in propulsion and power systems. Significant advances in computational power over the past decades have enabled detailed simulations of complex thermo-fluid processes in these systems. However, there are still many aspects of the underlying physics that are not currently accounted for with sufficient accuracy. Challenges exist with respect to consistency in the formulation of LES, development of robust subfilter models, and understanding implementation requirements such as the local spatial and temporal resolution required for the subfilter models to perform accurately. Historically, the extension of LES for treatment of multiphysics systems has evolved by analogy over time, not rigorous evaluation of the basic assumptions that underpin standard practice. Thus, many of the assumptions used for multiphysics problems have not been formally justified or assessed. Similarly, traditional LES closures ignore many of the mathematical artifacts that arise from filtering multiscalar systems. For example, the equation of state, internal energy, and enthalpy must be filtered in a manner that is consistent with the mixing rules used. Thus, the resultant covariance fields associated with scalar-scalar interactions must be considered but are typically neglected. The same is true for the filtered viscous stress tensor, energy diffusion flux, and mass diffusion fluxes. Additional terms also appear in the filtered energy equation that must be considered. Neglecting these terms creates inconsistencies that can lead to erroneous conclusions, which significantly complicates the model development process. These potential issues will be explored to illuminate important focal points related to the development of advanced models and more robust application of LES for the prediction of complex thermo-fluid processes.
Bio: Joe Oefelein is a Professor in the Guggenheim School of Aerospace Engineering at the Georgia Institute of Technology. Prior to this he was a Distinguished Member of Technical Staff at Sandia National Laboratories, Combustion Research Facility (2000 – 2017), and a Research Associate in the Department of Mechanical Engineering at Stanford (1997 – 2000). He received a PhD in Mechanical Engineering from Penn State in 1997.
His research interests are interdisciplinary, with focus on the theory, numerical modeling, and analysis of complex fluid flows where turbulence interacts with a multitude of strongly coupled fluid dynamic, thermodynamic, transport, chemical, multiphase, and heat transfer processes. Concurrent interests are focused on computational fluid dynamics and massively parallel high-performance computing with emphasis on the large-eddy-simulation and direct-numerical-simulation techniques.
Oefelein is a Fellow of The Combustion Institute, Fellow of the American Society of Mechanical Engineers (ASME), Associate Fellow of the American Institute of Aeronautics and Astronautics (AIAA), and active in the American Physical Society (APS), and Society of Automotive Engineers (SAE). He is an Associate Editor for the Journal of Propulsion and Power and a member and past Chair of the AIAA Propellants and Combustion Technical Committee.