Julian Domaradzki
University of Southern California
Seminar Information
Engineering Building Unit 2 (EBU2)
Room 479
Seminar Recording NOT Available
Large eddy simulations (LESs) of turbulence require subgrid-scale (SGS) models to account for loss of physical information caused by numerical resolution insufficient to capture all dynamically relevant scales of motion. Autonomous large eddy simulations can be defined as LES where a SGS model is not postulated but obtained from actual LES data in the course of simulations. In the present work we show how the subgrid-scale energy transfer among known, resolved scales in LES, and its scale/wavenumber distribution can be obtained directly from the evolving LES velocity fields. This information, when cast in the form of a spectral eddy viscosity, forms the basis of the method for self-contained LES without use of extraneous SGS models. It is shown that the only external physical information input required in the method is ultraviolet scaling of the energy flux, known from theories of the inertial range dynamics. The method is tested in LESs of isotropic turbulence at high Reynolds number where the inertial range dynamics is expected and for lower-Reynolds-number decaying turbulence under conditions of the classical Comte-Bellot, Corrsin experiments. I will conclude with remarks about implementing the method in the physical space representation and substituting input from theories of turbulence by machine learning techniques.
Julian A. Domaradzki received Ph.D. in Theoretical Physics from University of Warsaw, Poland, in 1979. After postdoctoral positions at Princeton University (Geophysical Fluid Dynamics Lab) and MIT (Mathematics) he joined University of Southern California in Los Angeles in 1987. Since 1997 he has been a Professor in the Department of Aerospace and Mechanical Engineering in the Viterbi School of Engineering. He is an author or co-author of over 250 scientific contributions, including 75 journal papers, with focus on turbulence theory, modeling, and numerical simulations. His professional background includes a number of visiting positions (Technical University in Munich; Université Libre in Brussels; Technical University in Dresden; ETH in Zürich; Tokyo Technical University; German Aerospace Establishment in Göttingen) and several scientific honors (Associate Fellow of the American Institute of Aeronautics and Astronautics (2011), Fellow of the American Physical Society (2008), Ouverture Internationale Award (2006), Invitation Research Fellowship of Japan Society for the Promotion of Science (2000), Alexander von Humboldt Research Award (1992) and Fellowship (1980), and USC Northrop Research Faculty Award (1991)). Service contributions include positions of AME Department Chair (2017-2020) and Associate Chair (2005-2008); Associate Editor, Journal of Turbulence (2013-2019); Chair of the organizing committee, 63th Annual Meeting of the American Physical Society's Division of Fluid Dynamics, Long Beach, California (2010).