The Department of Mechanical, Materials, and Aerospace Engineering presents the Nagib and Kalpakjian Annual Lecture on Turbulence. This year’s speaker is Ivan Marusic, Redmond Barry Distinguished Professor in the Faculty of Engineering and Information Technology at The University of Melbourne, who will present a lecture titled, “Scale-Interactions and Energy-Efficient Drag Reduction in Wall-Bounded Turbulent Flows” November 18 from 12:45–1:45 p.m. in Rettaliata 104.

The lecture will be followed by an event unveiling the newest inductee to the MMAE Hall of Fame, Lois Graham.

Abstract: Skin-friction drag limits the speed and efficiency of many critical transportation and energy systems, including pipelines, airplanes, ships, and submarines. Spanwise surface oscillation has been shown to be an effective drag reduction strategy for such wall-bounded turbulent flows at low to modest Reynolds numbers (friction Reynolds numbers up to 1,000). An open question has been whether such drag reduction is possible at high Reynolds number (order 104–105), as encountered in practice, and in an energy-efficient way. Here, Ivan Marusic will present experimental measurements of substantial drag reduction at friction Reynolds numbers up to 12,800 using spanwise surface oscillations. The drag reduction is found to occur via two distinct physical pathways. The first pathway, recognized from previous studies, involves actuating the surface at high frequencies, comparable to those of the small-scale eddies that dominate turbulence near the surface. The second pathway, however, is new and leverages actuation at low frequencies comparable to those of the large-scale eddies farther from the surface. Importantly, this is accompanied by net-power savings due to the low actuation frequencies used and suggests further benefits as the Reynolds number increases. Insights into the underlying mechanism for drag reduction, via non-linear scale interactions, will be discussed.

Ivan Marusic Biography: Ivan Marusic is a Redmond Barry Distinguished Professor in the Faculty of Engineering and Information Technology at the University of Melbourne. His research is primarily in experimental and theoretical studies of turbulence at high Reynolds numbers, including using atmospheric surface layer flows and large wind tunnel facilities. Over his career, he has held a number of prestigious fellowships, including an Australian Research Council (ARC) Laureate Fellowship (2012–2017), an ARC Federation Fellowship (2006–2011), and a Packard Fellowship in Science and Engineering (2001–2006). He is the recipient of the Stanley Corrsin Award from the American Physical Society and is a fellow of the American Physical Society, Australasian Fluid Mechanics Society, Australian Academy of Technology and Engineering, and the Australian Academy of Science.

Hassan Nagib Biography: Hassan Nagib is the John T. Rettaliata Endowed Chair of Mechanical and Aerospace in Armour College of Engineering at Illinois Institute of Technology. Nagib was the founding director of Illinois Tech’s Fluid Dynamics Research Center. His areas of specialty are fluid mechanics, turbulent flow, and flow management and control. At Illinois Tech, he has served as the MMAE department chair, dean of Armour College, academic vice president, and chief scientist for IIT Research Institute (IITRI). Nagib is the recipient of several prestigious honors including being a fellow of the American Physical Society, the American Association of Advancement of Science, the American Institute of Aeronautics and Astronautics, and the American Society of Mechanical Engineers. While based at Illinois Tech for more than half a century, Nagib has also been a visiting faculty on several occasions at Stanford University, California Institute of Technology, KTH Royal Institute of Technology, the Swiss Federal Institute of Technology Lausanne, University of Erlangen–Nuremberg, and served as a Tewkesbury Fellow in the Department of Mechanical Engineering at the University of Melbourne.