Seminar "Alternation of turbulent boundary layer with bubble injection" by Prof. Yuichi Murai

[Speaker]

Prof. Yuichi Murai
Professor, Faculty of Engineering
Hokkaido University
President of Japan Society for Multiphase Flows

[Abstract]

The injection of gas bubbles into a turbulent boundary layer of a liquid phase has multiple different impacts on the original flow structure, affecting heat and momentum transfer on the wall significantly. While bubbles in stationary water are just thermal resistance for heat, they rather promote heat transfer in turbulent flow due to their intrinsic motion amplified by turbulent ambience. In contrast, bubbles produce frictional drag reduction in highly turbulent boundary layer. This phenomenon has been utilized for marine vessels to save fuel as well as reduction of CO2 emission. In this presentation,  these phenomena will be explained based on several experiments introducing theories of two-phase flow, experimendal discoveries from PIV, and use of ultrasound monitoring techniques applied for high-Reynolds number turbulent boundary layer.

[Bio]

1992-1995 Ph.D., The University of Tokyo
1996-2000 Assistant Professor, Fukui University (mainly nuclear engineering)
2001-2002 Research fellow, Imperial College London (internal combustion engine)
2003-2009 Associate Professor, Hokkaido University (mainly PIV development)
2010- Full Professor, Hokkaido University (mainly ultrasound Doppler velocimetry)
2018- Editor, Experiments in Fluids
2023- President of Japan Society for Multiphase Flows