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Large-scale LES Analysis in Real Industrial Applications - From the Historical Perspective of CFD

AMS Seminar Series

Speaker: Kozo Fujii, Tokyo University of Science

Presentation

Seminar Slide Deck (PDF-45.8MB)

Abstract

With the rapid progress of computer performance, CFD made remarkable progress and became an important tool for analysis and design in both academic study and industrial engineering. Turbulence research with more sophisticated models, on the other hand, stayed in simple geometries under relatively low Reynolds number flow conditions. The story is now changing, and high-fidelity simulations with LES are becoming used even in practical applications of industries. Computer progress is one of the reasons, but, more importantly, approaches that can inherently capture nonlinear and stiff nature of fluid phenomena are becoming needed.

After flashing back over 30 years of CFD with HPC to find out why such change is happening, along with a short discussion of aero-acoustic applications, mechanism of flow separation control by DBD plasma actuators will be discussed based on a series of HPC simulations of the flows over airfoils. The device is shown to be very effective for controlling flow separation. Strong authority of this device is strongly related to the transition to turbulent flows, but the study reveals that there is another important factor. Guidelines on how to use this device efficiently for flow separation control is derived based on the observations and post-analysis of the simulation results.

Fluid behavior in a very small region both in time and space may totally change global flow structures and aerodynamic performance because of its nonlinear nature. As a part of the summary, the author would like to emphasize that large-scale high-fidelity simulations are sometimes necessary even in the preliminary stage of the design process.

Biography

Kozo Fujii is a Professor at the Tokyo University of Science in Japan since March 2015. He was a professor at the Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA) since 1987, before joining the Tokyo University of Science. He received his Ph.D. from the University of Tokyo in 1980, and after spending a few years at NASA Ames Research Center and others, he came back to the ISAS. now in JAXA. He was also a professor in the Department of Aeronautics and Astronautics, University of Tokyo until 2015 and was a thesis advisor for many CFD researchers now active in the world.

He has been working on CFD for more than 40 years since the early days of CFD in aerospace. His research interests include a variety of studies on aerodynamics, but recently focus mainly on aero-acoustics and flow control. He gave a number of keynote plenary lectures such as at the 7th ICCFD in 2012, 4th ICJWSF in 2013, Parallel CFD in 2015, TILDA symposium in 2016, and EUROMECH Colloquium in 2018. He received the “Daniel & Florence Guggenheim Award” from the International Council of Aeronautical Sciences (ICAS) in 2004, among many other awards received. He became a Fellow of AIAA in the same year (2004).

Fujii has been leading HPC Infrastructure (HPCI) activities in Japan. He was the president of HCPI consortium in Japan until 2016, and is a vice chair of the governmental committee that decides the future direction of HPCI systems, including the Post-K computer and its applications. He has been one of the 210 council members of Science Council of Japan since 2014.