Conferences, Lectures, & Seminars
Events for March
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AME Department Seminar
Wed, Mar 07, 2012 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Speaker: Young W. Kwon, Distinguished Professor. Dept. of Mechanical & Aerospace Engineering. Naval Postgraduate School. Monterey, California, USA. ywkwon@nps.edu
Talk Title: Analysis of Multiscale and Multiphysics Problems
Abstract: In order to better understand the behavior of materials and structures, multiscale and multiphysics analyses are useful and sometimes critical. For example, progressive damage and failure of laminated composite structures can be modeled successfully using the multiscale modeling technique. By doing so, damage and failure in composites can be described in terms of the constituent materials such as fibers and binding matrix regardless of the layer orientation, fiber architecture in each layer, etc. In other words, any damage and failure mode can be described in terms of fiber breakage, matrix cracking, and interface debonding. On the other hand, when a composite structure is in contact with water and subjected to dynamic loading, fluid-structure interaction plays an important role because composite has very comparable density as the water. Therefore, a multiphysics analysis is necessary to understand and predict the structural behavior with fluid-structure interaction. Various multiscale and multiphysics problems are presented.
Host: Prof. Veronica Eliasson
More Info: http://ae-www.usc.edu/seminars/index.shtml#upcomingLocation: Seaver Science Library (SSL) - 150
Audiences: Everyone Is Invited
Contact: April Mundy
Event Link: http://ae-www.usc.edu/seminars/index.shtml#upcoming
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AME Department Special Seminar
Thu, Mar 08, 2012 @ 11:00 AM - 12:00 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Speaker: Oscar M. Curet, Postdoctoral Fellow. School of Engineering Brown University. Providence, RI.
Talk Title: Biological Propulsion, Biomimetics, and Flow Control: The Mechanics of Fin Propulsion and a Self-Excited Flapper
Abstract: Swimming and flying animals have a remarkable ability to navigate through complex environments. As they propel themselves, they interact with the surrounding fluid medium. This fluid-animal interaction plays a fundamental factor in how animals actuate their muscle as well as how they have evolved. In order to incorporate biological-based designs into the next generation of underwater or air vehicles, it is crucial to understand the role of fluid dynamics in animal locomotion. In this talk, I will focus on two highly maneuverable animals: knifefish and bats. A knifefish uses an electric field to "see" at night in the Amazon River, and it propels itself using a long ribbon fin to navigate around its complex environment. I will present experimental and computational work that unveils the mechanical basis of fin propulsion and the rich locomotor capability of these fish. In the second part of the talk, I will present a physical model to explore an open and controversial question in the evolution and origin of bat flight: how bats' ancestors could have begun to employ flapping motions in their flight. I explore this question using a simple physical model which captures two key biological features: compliance and camber. The model is composed of a cantilevered flat plate (capturing the compliance) with a hinged trailing flap (modeling the variable camber). For slow wind speeds, the model is stationary, but above a critical wind speed, the wing starts to oscillate due to an aeroelastic instability. A positive angle of attack on the wing results in a positive lift force. Moreover, this lift force is significantly enhanced once the wing starts to oscillate. I will present particle image velocimetry (PIV) data to shed light on the aerodynamics of the self-excited flapping wing and to identify the mechanisms that generate the enhanced lift force. I will also discuss the implications of the results on the evolution of powered biological flight.
Host: Prof. Geoff Spedding
More Info: http://ae-www.usc.edu/seminars/index.shtml#upcomingLocation: Robert Glen Rapp Engineering Research Building (RRB) - 208
Audiences: Everyone Is Invited
Contact: April Mundy
Event Link: http://ae-www.usc.edu/seminars/index.shtml#upcoming
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AME Department Seminar
Wed, Mar 21, 2012 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Speaker: Bin Liu, Postdoctoral Research Associate. School of Engineering. Brown University. Providence, RI
Talk Title: Helical Swimming in Complex Fluid Media
Abstract: Many bacteria swim by rotating helical flagella. In Nature, these cells often live in a complex fluid environment, such as suspensions of polymers and other micro-scale structures. To explore the physics on how such complex environments affect the bacterial motility, the helical swimmer is simulated by a model system - a motorized helical coil that rotates along its axial direction. When the helix is immersed in a viscoelastic fluid, a model fluid of polymer suspensions, there is an increase in the swimming speed as compared with the Newtonian case. The enhancement is maximized when the rotation rate of the helix matches the relaxation time of the fluid. The magnitude of enhancement depends not only on the elasticity of the fluid but also on the geometry of the helix. In the second part of my talk, I will discuss on how such helical swimming is affected by spatial confinement of micro scales, such as a porous medium. As a reduced order model, the porous media is regarded as cylindrical cavities with solid walls. A modified boundary element method is introduced here to make full use of the helical symmetry. This method allows us to investigate a situation that the flagella are tightly confined by solid wall. To our surprise, at fixed power consumption, a highly coiled swimmer swims faster in a narrower confinement, while an elongated one swims faster in a cavity with a wider opening. These phenomena are explained with simple physical picture.
Host: Prof. Geoff Spedding
More Info: http://ae-www.usc.edu/seminars/index.shtml#upcomingLocation: Seaver Science Library (SSL) - 150
Audiences: Everyone Is Invited
Contact: April Mundy
Event Link: http://ae-www.usc.edu/seminars/index.shtml#upcoming
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AME Department Seminar
Wed, Mar 28, 2012 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Speaker: Attila Bergou, Postdoctoral Researcher. School of Engineering. Brown University. Providence, RI.
Talk Title: How Do Flying Animals Reorient Themselves?
Abstract: The flying ability of animals is spellbinding: they can catch their prey in midair, execute precise maneuvers, sustain flight for incredible amounts of time. For centuries scientists and engineers have toiled to unlock the secrets behind their flight adeptness. This research has lead to many breakthroughs in our understanding of the behavior and force production of fixed and flapping wings and in no small part lead to the invention of the airplane. Despite the centuries of research, and many breakthroughs, fundamental aspects of animal flight still elude understanding. One domain with surprising gaps in knowledge is how animals actuate and control flight maneuvers.
Here, I will present experimental and computational work showing the mechanisms behind flight maneuvers performed by two decidedly distinct flyers: fruit flies, and bats. In particular, we analyze how these animals reorient themselves in the air. Our organismal experiments, and novel motion tracking algorithms allow us to reconstruct the subtle wing and body kinematics of these animals at a level of detail previously unavailable. From these intricate kinematics, and morphological measurements, we build detailed dynamical models to infer the surprising mechanisms behind these maneuvers.
Host: Prof. Geoff Spedding
More Info: http://ame-www.usc.edu/seminars/index.shtml#upcomingLocation: Seaver Science Library (SSL) - 150
Audiences: Everyone Is Invited
Contact: April Mundy
Event Link: http://ame-www.usc.edu/seminars/index.shtml#upcoming