Keynote Speakers (tentative)

  • Name Koji Fukagata
    Affiliation Keio University
    Biographical Sketch Koji Fukagata is a Professor at Department of Mechanical Engineering, Keio University, Japan. His research focuses on flow control such as turbulent drag reduction and computational fluid dynamics. Also, he has recently started a JSPS KAKENHI project on application of machine learning for feature extraction in turbulent flows.
    Fukagata completed his PhD in 2000 at the Royal Institute of Technology (KTH), Sweden, as well as at The University of Tokyo, Japan. He served as a postdoctoral fellow and research associate at The University of Tokyo from 2000 to 2007, and moved to Keio University in 2007, and has served as a full professor at Keio University since 2015.
    Fukagata received the Award for Distinguished Young Researcher in Fluid Mechanics (Ryumon Award) from Japan Society of Fluid Mechanics (JSFM) in 2008, Award for Outstanding Paper in Fluid Mechanics from JSFM in 2013, and Fluids Engineering Frontier Certificate of Merit from JSME-FED in 2014. He now serves as an Editor of Flow, Turbulence and Combustion (Springer).
    Presentation Title Application of machine learning to fluid mechanics problems
    Abstract Application of machine learning is currently one of the hottest topics in the fluid mechanics field. While machine learning seems to have a great possibility, its limitations should also be clarified. In our group, we have started a research project to construct a nonlinear feature extraction method by applying machine learning technology to “turbulence big data,” extracting the nonlinear modes essential to the regeneration mechanism of turbulence, and deriving the time evolution equation of those nonlinear modes. In this presentation, we will introduce some examples on learning and regeneration of temporal evolution of cross-sectional velocity field in a turbulent channel flow using convolutional neural network (CNN). We will also introduce the application of CNN for super-resolution analysis and extraction of low-dimensional nonlinear modes for flow around a bluff body accompanying vortex shedding. We also introduce our attempts to interpret the nonlinear modes extracted by CNN autoencoder and to use them for an advanced design of flow control, as well as an attempt for uncertainty quantification and applications to experimental data.
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  • Name Ekaterinaris, John A.
    Affiliation Embry-Riddle Aeronautical University
    Associate editor of the Journal Progress in Aerospace Science (JPAS)editor in chief of the Journal Aerospace Science and Technology (AESCTE)
    Biographical Sketch Dr. John A. Ekaterinaris received his B.S. in Electrical and Mechanical Engineering from the Aristotle University of Thessaloniki in Greece in Oct. 1977. Started graduate studies in the US in 1981 and revived his M.Sc. in Mechanical Engineering in 1982 and his Ph.D. from the School of Aerospace Engineering in 1987, both at the Georgia Institute of Technology, Atlanta GA.
    Between 1987 – 1995, worked at NASA–Ames Research Center at Moffett Field CA, and at the same time he was faculty at the Naval Postgraduate Scholl at Monterey CA. He took a Senior Research Scientist position at RISOE National Laboratory in Denmark between 1995 – 1997 where he worked on wind energy, he returned to CA and worked at Nielsen Engineering and Research (NEAR) between 1997 – 2000.
    In Oct. 2000 he took the Research Director position at FORTH/IACM, where he remained until 2005. In Sept. 2005 he joined the faculty of Mechanical and Aerospace Engineering at the University of Patras. He joined the faculty of Embry-Riddle Aeronautical University in August 2012 where he is currently teaching and performing research.
    His interests are computational mechanics (including aerodynamics, magnetogasdynamics, electromagnetics, aeroacoustics, flow transition, turbulence research, and flow structure interaction), high order methods for PDEs, multiscale phenomena, stochastic PDE’s, and biomechanics and more recently machine learning and uncertainty quantification. He is author of over 60 journal papers. He has been member American Institute of Aeronautics and Astronautics (AIAA), where he served as member at the Flight Mechanics and Fluid Dynamics Technical Committees, and AIAA associate fellow of since 1985.
    He performed funded research in the US and in Europe with the European Space Agency (ESA), and through the EU framework programs. He also performed funded research thought the offices of AFOSR and ARO. He is associate editor of the Journal Progress in Aerospace Science (JPAS) and editor in chief of the Journal Aerospace Science and Technology (AESCTE).
    Presentation Title Simulations requirements ensuring accurate predictions of vortex dominated fields and vortices generated from wings and rotor blades
    Abstract Accurate resolution of vortex dominated fields generated by wing and rotor blades is important for the aerospace industry and concentrated the efforts of researchers and engineers from the early stages of computational fluid dynamics and a new emerging technology. To date accurate prediction of vortex dominated flow fields still is a subject of interest. For industrial scale applications such as aircraft and rotorcraft vortical flows only simulations performed with the Reynolds averaged Navier-Stokes (RANS) equations are feasible while large eddy simulations (LES) can hardly reach the Reynolds numbers of practical applications in aerodynamics and remains a research tool. It will be demonstrated that despite the tremendous increase of resources, computational speed, and the progress in turbulence modeling achieved in the last years, the high resolution requirements and turbulence modeling deficiencies are still an issue for industrial scale applications. In this presentations some remedies to these issues are suggested and simulation examples for leading edge vortices, dynamic stall, and wing tip vortices generated by fixed and rotating blades are shown. The improvements achieved are highlighted and the remaining deficiencies are discussed.
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  • Name Huihe Qiu
    Affiliation Head of Department of Mechanical and Aerospace Engineering Director, Building Energy Research Center, FYTGS
    The Hong Kong University of Science & Technology
    Biographical Sketch Professor Huihe Qiu is Head and Professor in the Department of Mechanical and Aerospace Engineering at The Hong Kong University of Science & Technology (HKUST) and Director of the Building Energy Research Center (BERC) of the HKUST Nansha Fok Ying Tung Graduate School. Professor Qiu received his Ph.D. degree from Institute of Fluid Mechanics, LSTM, at the University of Erlangen, Germany. Professor Qiu’s research areas are in multiphase flow and heat transfer, optical diagnostics, flapping wing aerodynamics, and nano- and microfluids. Professor Qiu is Editor-in-Chief/Editor/Associate Editor of four international journals and a member of the editorial board for more than 10 international journals. He has been invited to give 25 plenary and keynote speeches in International Conferences. He is the recipient of the Best Paper Award of Measurement Science & Technology, Institute of Physics (IOP) in 1994, Philips Outstanding Paper Award (2012), ASME Best Poster Award (2010), Best Paper Award, 2nd World Congress on Mechanical, Chemical, Material Engineering (2016), Best Paper Award, 4th International Conference on Heat Transfer and Fluid Flow (2017), Best Paper Award, 10th International Conference on Nanotechnology: Fundamentals and Applications (2019), The State Scientific and Technological Progress Award (SSTPA) and the Scientific and Technological Achievement Award from the State Education Commission.
    Presentation Title Synergetic Flow Control and Wing Flexibility Effect in a Tandem Wing Insect Flight
    Abstract The behavior of insect flight is of significant interest for designing human-engineered flapping-wing-based micro air vehicles. Tandem wing insects, such as dragonflies reveal quick, demanding maneuvers or takeoff, steady flight and hovering utilizing different phases between the fore- and hindwings. The forewing and the hindwing of a dragonfly have different geometry that could be an evolutionary specialization for better aerodynamic performance via sophisticated wing pitch control. Under different extent of wing pitching by the wing root musculature, the fore- and hindwings could exhibit different shape deformation and aerodynamic characteristics as a result of passive shape deformation. It is debatable whether the pitching motion of an insect wing is only induced passively by aerodynamic and inertial forces or some of the pitching are consciously actuated. Furthermore, the vortex-wing interaction between the forewing and hindwing is also very complex as it involves forewing’s leading edge vortex and trailing edge vortex shedding and hindwing vortex capturing which is affected by wing kinematics, wing flexibility, wing spacing and wing shape.
    In this talk, the vortex-wing interactions and active/passive natures of wing pitching in several observed wing kinematics, including the wing motions of tethered and free-fly dragonflies are presented. We measured the flow around the flapping wings using time-resolved particle image velocimetry (TR-PIV) to investigate the consequences of shape and the pitching mechanisms of the wings on the aerodynamics of dragonflies. The dynamic deformation of the wings was optically probed. The flow fields and pitching angle variations of the naturally actuated wing of the dragonfly were compared with that of the same wing artificially actuated only by flapping motion. To reveal the extent of active pitching, the flow fields and pitching angle of the actively actuated wing of the dragonfly were compared with that of the same wing artificially actuated only by flapping motion. We found that the trailing edge vortex dynamics and the wake were affected by the wing shape only for the in-vivo experiment with muscle induced pitching. These results suggest the pitching motion of the wings can be active and passive depending on flight models of insect flight. These results provided quantified evidence to the extent and importance of the pitching motion of the wings in dragonfly flight The spanwise variation in vortex-wing interactions can be exploited in the design of artificial wings to achieve greater agility and higher efficiency. The results of this work can be useful for the design of wings, their actuation mechanism, and the in-flight kinematics control of flapping wing micro air vehicles (MAVs).
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  • Name Jinjun Wang
    Affiliation School of Aeronautic Science and Engineering, Beihang University
    Biographical Sketch Prof. Jinjun Wang is the Director of Fluid Mechanics Key Laboratory, Ministry of Education of China. Prof. Wang received his Bachelor and Master degrees from Wuhan University of Hydraulic and Electric Engineering in 1983 and 1986, respectively. He obtained his Ph.D. degree from Tsinghua University in 1990, and he was a postdoctoral fellow in BUAA during 1990-1991. Since 1993, he has been a full professor in BUAA. He was the head of Department of Aircraft Design and Applied Mechanics (1997-2003) in BUAA. He is the recipient of National Natural Science Foundation of China(NSFC) for Outstanding Youth Scientist Award (2004) and the Yangtze River Scholar Award (Distinguished Professor) from the Ministry of Education of China (2009). He is also the associate editor of Experiments in Fluids, Journal of Aircraft, Theoretical and Applied Mechanics Letters, and the editorial board members of Science China-Technological Science, ACTA MECHANICA SINICA and Chinese Journal of Aeronautics. He organized 4th International Conference on Experimental Fluid Mechanics in 2014 and 14th Asian Syposium on Visualization in 2017. He has published more than 100 papers in international archival Journals in Flow control, Turbulence, Aircraft Aerodynamics, including Journal of Fluid Mechanics, Physics of Fluids, Progress in Aerospace Sciences, AIAA Journal and Experiments in Fluids.
    Presentation Title Synthetic Jet Impinging onto Porous Walls
    Abstract Since the concept of synthetic jets was proposed in the 1950s, it has attracted great attention. By blowing and suction of fluid across the exit periodically, a synthetic jet is created. During an actuation cycle, the amount of fluid ejected from the exit is equal to that drawn in, therefore, synthetic jets are also named “zero-net-mass-flux” (ZNMF) jets. When a synthetic jet is actuated, a train of vortices is ejected into the flow field, which promotes the flow mixing and entrainment. On the other hand, the secondary flow structure induced by the vortex impinging onto a wall could improve the mass and momentum transfer of the near-wall flow. Thus, impinging synthetic jets are promising to develop as an efficient cooling method in the future.
    In the presentation, we will report the results from an experimental study on impinging synthetic jets by using laser induced fluorescence (LIF) and particle image velocimetry (PIV) techniques. Influences of stroke length and Reynolds number on the flow behavior of an impinging synthetic jet are analyzed. Special attention has been paid to the near-wall flow in order to build the links between the vortical structures and the characteristics of the wall jet, which is important for understanding of vortex/wall interaction mechanism as well as for the related heat transfer applications. Finally, vortex rings of a synthetic jet impinging onto porous walls with a constant surface porosity has been investigated to provide a better understanding of the mechanism of the interaction between vortex rings and complex boundaries.
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  • Name Henrik Alfredsson
    Affiliation FLOW, Department of Engineering Mechanics,
    KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
    Biographical Sketch P. Henrik Alfredsson is professor emeritus in Fluid Physics at KTH, Royal Institute of Technology, Sweden. He is an experimentalist focusing on fundamental studies of flow stability, transition and turbulence, as well as on applied areas such as wind energy, vehicle aerodynamics and engine flows.
    Alfredsson completed his PhD in 1983, became extra professor in 1986 and full professor of Fluid Physics in 1989, all at KTH. He was dean at KTH 1999-2003 and Guest professor at II Facolta di Ingegneria, Universita di Bologna Italy, 2007-2017. He has supervised more than 20 PhD students and 10 postdoctoral students in the Fluid Physics Laboratory at KTH.
    In 2005 he received (together with M. Matsubara) an award from the Japan Society of Fluid Mechanics for the paper "Disturbance growth in boundary layer subjected to free-stream turbulence". He is Elected Fellow of the American Physical Society, Division of Fluid Dynamics since 2012 with the citation: “For the development of innovative, creative and rigorous experimental methods leading to seminal contributions to our understanding of instabilities, transitional and turbulent flows”. He has authored and coauthored 140 papers published in refereed journals and his h-index is at present 38 (Web of Science).
    Presentation Title Rotating disks and cones – a centennial of von Kármán's 1921 paper
    Abstract In 1921 Theodor von Kármán presented a paper in the first issue of Zeitschrift für Angewandte Mathematik und Mechanik (ZAMM) with the title "Über laminare und turbulente Reibung". That paper is only 20 pages and deals with various aspects of boundary layers in 9 different sections, and certainly enough topics to result in several papers today. One of the sections develops the similarity theory of the laminar boundary layer on a rotating disk and another section deals with experimental results of the frictional resistance of rotating disks in the turbulent region. This talk will review results over the last 100 years since the work of von Kármán and the difference between rotating broad cones (including the disk) and rotating slender cones (including the cylinder) will be highlighted. The relevant parameters and mechanisms determining the instability will be discussed in the light of old and new results, with a focus on work over the last 10+ years at the Fluid Physics laboratory, KTH (see Kato et al, 2021 and references therein).
    Kato, K., Segalini, A., Alfredsson, P.H. & Lingwood, R.J. 2021 Instability and transition in the boundary layer driven by a rotating slender cone. J. Fluid. Mech. vol. 915, R4.
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  • Name Ephraim J. GUTMARK
    Affiliation Distinguished Professor of Aerospace Engineering and Engineering Mechanics, Ohio Regents Eminent Scholar
    Professor of Otolaryngology, UC Medical Center (secondary appointment)
    Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, OH 45221-0070, USA
    Biographical Sketch Dr. Gutmark is a Distinguished Professor of Aerospace Engineering and Engineering Mechanics and Ohio Regents Eminent Scholar at the University of Cincinnati (UC). In 2006 he was also appointed as a Professor of Otolaryngology. Since 2009 he is an Affiliated Professor of Mechanics at the Royal Institute of Technology in Sweden. He was a chaired Professor of Mechanical Engineering and the Chairman of the Mechanical Engineering Department at Louisiana State University (LSU). Prior to LSU, he was a Senior Research Scientist at the Research Department of the Naval Air Warfare Center in California.
    His research interests include aeroacoustics, fluid dynamics, Pulse/Rotating Detonation Combustors (PDC/RDC), heat transfer, combustion, afterburners, and propulsion.
    He is an Editor of Flow, Turbulence, and Combustion. He is a Fellow of the American Institute of Aeronautics and Astronautics (AIAA), Fellow of the American Physical Society (APS), and Fellow of the American Society of Mechanical Engineers (ASME), he was awarded the Einstein Fellowship in 2016. He is the recipient of the 2021 AIAA Aeroacoustics Award, 2013 ASME Fluids Engineering Award, Hanin International Lifetime Achievement Aerospace Award 2018, and is a Fulbright Specialist. He published 288 papers in refereed archival journals, 595 reviewed conference papers, and is a co-inventor of 76 USA and international patents.
    Presentation Title Flow and Acoustics of supersonic twin jets
    Abstract Some modern supersonic airplanes have two or more engines near each other. The supersonic exhaust jets can interact with each other and impact the flow structure of each other and the acoustic emissions from them. This presentation describes the interaction between two jets emanating from circular, low aspect ratio rectangular, and square nozzles that are in proximity to each other. The impact of the interaction between the jets on the flow field and the near and far field acoustics and compares them to single nozzles of the same geometry is shown. The mode of interaction for different nozzle geometry and nozzle pressure ratio (NPR) will be discussed. Pressure waves that propagate between the jets change their mutual shock structure and shear layer evolution, modifying the acoustic field normal and in-line with the common plane of the two jets.
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