Recently, Prof. Giacomin visited the State Key Laboratory for Turbulence and Complex Systems (LTCS). Dr. Giacomin is Professor of Chemical Engineering and of Mechanical and Materials Engineering at Queen’s University at Kingston in Canada where he holds the title of Tier 1 Canada Research Chair in Rheology. He received his bachelor’s and master’s degrees in Chemical Engineering from Queen’s University in Kingston, before joining the Research Division at DuPont Canada. He then received a PhD in Chemical Engineering from McGill University under Prof. John Dealy. He has been Professor of Mechanical Engineering at the University of Wisconsin, where for twenty years he chaired its Rheology Research Center. He has held visiting professorships at McGill University, the University of Sherbrooke, the Swiss Federal Institute of Technology, the Paris School of Mines, the National University of Singapore, Chung Yuan University near Taipei, Yunlin University, in southern Taiwan, and Shandong University in mainland China. He is a former President of The Society of Rheology, a friendly association of some 1,600 rheologists. Giacomin also serves as Editor-in-Chief of Physics of Fluids.
Prof. Giacomin gave a lecture titled “Advances in Large-Amplitude Oscillatory Shear Flow of Polymeric Liquids” on June 9 in the College of Engineering (COE). He introduced that in 1935, Andrew Gemant conceived of the complex viscosity, a rheological material function measured by “jiggling” an elastic liquid in oscillatory shear. This test reveals information about both the viscous and elastic properties of the liquid, and about how these properties depend on frequency. The test gained popularity with chemists when John Ferry perfected instruments for measuring both the real and imaginary parts of the complex viscosity. In 1958, Cox and Merz discovered that the steady shear viscosity curve was easily deduced from the magnitude of the complex viscosity, and today oscillatory shear is the single most popular rheological property measurement. With oscillatory shear, we can control two things: the frequency (Deborah number) and the shear rate amplitude (Weissenberg number). When the Weissenberg number is large, the elastic liquids respond with a shear stress over a series of odd-multiples of the test frequency. Prof. Giacomin shared recent progress of the mechanism of the high frequency response with many faculty and students of COE in his creative bilingual lecture in English and Mandarin. He will stay and discuss scientific problems and further collaboration with LTCS for two weeks.