Gretar Tryggvason

Department of Mechanical Engineering, Johns Hopkins University, Baltimore，USA

Professor Gretar Tryggvason is the Charles A. Miller, Jr. Distinguished Professor at the Johns Hopkins University and the head of the Department of Mechanical Engineering. He received his PhD from Brown University in 1985 and was on the faculty of the University of Michigan in Ann Arbor until 2000, when he moved to Worcester Polytechnic Institute as the head of the Department of Mechanical Engineering. Between 2010 and 2017 he was the Viola D. Hank professor at the University of Notre Dame and the chair of the Department of Aerospace and Mechanical Engineering. 

Professor Tryggvason is well known for his contributions to computational fluid dynamics; particularly the development of methods for computations of multiphase flows and for pioneering direct numerical simulations of such flows. He served as the editor-in-chief of the Journal of Computational Physics 2002-2015, is a fellow of APS, ASME and AAAS, and the recipient of several awards, including the 2012 ASME Fluids Engineering Award and the 2019 ASTFE Award.

Title: Numerical Simulations of Complex Multiphase Flows

Abstract: Computations have played a transformative role in our current understanding of multiphase flows and direct numerical simulations, where the governing continuum equations are solved accurately for systems that are large enough so that meaningful statistical quantities can be computed, are rapidly becoming routine, at least for systems where the physics is simple enough, such as disperse flows of bubbles and drops. Those simulations yield enormous amount of data that, in addition to providing physical insights, opens up new opportunities for the development of lower order, or coarser, models that describe the average or large-scale behavior. We discuss efforts to do so, including the use of machine learning to extract closure models from the data for bubbly flows as well as processes to coarsen more complex flow fields while retaining sharp interfaces. In addition, success with relatively simple systems calls for simulations of more complex problems and we discuss briefly initial efforts to examine three-phase flows, as found in mineral processing, for example, as well as multiscale strategies to capture small scale structures such as thin films and mass boundary layers, using analytical and semi-analytical models.