Melissa Green, University of Minnesota
Tuesday 16 April, 10:40-11:00
Melissa Green received her BS in Aerospace Engineering from the University of Notre Dame and her PhD in Mechanical and Aerospace Engineering from Princeton University. She was an NAS/NRC Postdoctoral Research Associate at the Naval Research Laboratory from 2009 to 2011. In 2012, she started her faculty career as an Assistant Professor in the Mechanical and Aerospace Engineering Department at Syracuse University, and joined the Aerospace Engineering and Mechanics Department at the University of Minnesota as an Associate Professor in 2021. She received the Air Force Office of Scientific Research Young Investigator Award in 2014, and was selected as an Associate Fellow of AIAA in 2020. She won her department’s teaching award in 2015 and 2020, and the Dean’s Award for Excellence in Engineering Education in 2016. Her research interests are primarily in the field of experimental fluid dynamics, particularly in vortex-dominated and bio-inspired applications. 

A two degree-of-freedom fish platform was used to investigate the relationship between simplified fish kinematics and propulsive performance. Its design, construction, and actuation provide control of maximum trailing-edge excursion; heave-to-pitch ratio; and phase offset between the tail and caudal fin while the oscillation frequency is fixed. Thrust and power input were measured to evaluate the performance of each parameter set while the flow field was measured using stereo particle image velocimetry. A parametric sweep of all parameters, excluding frequency, was used to evaluate the performance and flow field. This space included and extended beyond the known biological space. It was found that within the biological range of 0.20 < St < 0.40, the efficiency was maximized for a heave-to-pitch ratio of 0.75 and a phase offset of 115 degrees. For a given heave-to-pitch ratio, the thrust was maximized for a phase offset between 93 and 115 degrees and the power input was minimized for a phase offset between 115 and 135 degrees depending on the amplitude of the trailing-edge excursion. This work provides insight into the relationship between near-field vortex dynamics (finlet vortex, leading-edge vortex, and forming trailing-edge vortex) and propulsive performance.

 

Hao Liu, Chiba University 
Wednesday 17 April, 10:40-11:00
Hao LIU is professor of mechanical engineering at Chiba University, and director of Center for Aerial Intelligent Vehicles (CAIV). He is a fellow of the Japan Society of Mechanical Engineers (JSME). He is selected among Top Leading Scientists in the fields of engineering & technology (research.com) and Top 2% Scientist (Stanford University). Prior to joining Chiba University in 2003, he was a senior research scientist in RIKEN (The Institute of Physical and Chemical Research). He is the author and a co-author of more than 650 papers in journals and conferences, mainly dealing with computational mechanics, biomechanics in flying and swimming, fluid-structure interaction, biomimetics, insect-inspired micro air vehicles, and bio-inspired engineering as well as multi-scale, multi-physical modeling of the cardiovascular system, and AI-driven predictive medicine. He has received several awards including JACM Computational Mechanics Award, and his professional views have been quoted in several news media, including NHK, AFP, Thomson Reuter, and most major newspapers in Japan, including Yomiuri-Shimbun, Asashi-Shimbun, Nihon Keizai Shimbun, Nikkan etc.

Vortices and Forces in Insect Flight: A Review
In this talk, I highlight the state of the art of vortex-dominated, unsteady flapping aerodynamics from the viewpoint of diversity and uniformity associated with dominant vortices, particularly of the relevant physical aspects of the flight of insects from tiny featherwing beetle to hawkmoth in the low Reynolds-number (Re) regime of 10⁰ to 10⁴. An overview is given of the main technical aspects comprising the leading-edge vortices, vortices during wing rotation, wing-body interaction, flexible wing- and wing hinge-induced wing-flow interaction, wing-wake interactions from a combined theoretical, computational, and experimental perspective. Finally, I will give a summary of the main results and the future issues in the field.

 

Wei Hou, California Institute of Technology
Thursday 18 April, 10:40-11:00
Wei Hou is a graduate researcher at California Institute of Technology working with Prof. Tim Colonius. He works on high-performance numerical algorithms for turbulent flow simulation and operator-theoretic methods in flow analysis. He received his BS in Aerospace Engineering and Applied Mathematics from University of California, Los Angeles, where he worked with Prof. Jeff Eldredge to apply machine learning techniques to solve problems in gust detection. His research interests include computational methods in scientific computing, high-fidelity flow simulations, and data-driven methods in fluid dynamics. 

Fast three-dimensional stability and resolvent analysis for external flows about arbitrary spanwise homogeneous geometries
We introduce a computationally efficient method to conduct three-dimensional stability and resolvent analyses of spanwise periodic external flows. Our method utilizes the Immersed Boundary (IB) method with a fast lattice Green's function (FLGF) solver for the associated Poisson-like equation. The method is also compatible with local mesh refinements, enabling it to handle different length scales efficiently.  We demonstrate the capability of this method to handle a wide range of length scales by conducting a stability analysis of the flow past a cylinder at Re = 63 with a small control cylinder in its wake. We also present some preliminary results of three-dimensional resolvent analyses for the flow past a cylinder at Re = 45 and 188.