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Colloquium: Dr. Jeff D. Eldredge

Bourns Hall A265

Biolocomotion in Fluids Through Analysis of Canonical Problems

Dr. Jeff D. Eldredge
Mechanical and Aerospace Engineering Department
University of California, Los Angeles

Most aquatic creatures achieve motility through the dynamic interaction of their flexible body with the surrounding medium. This flexibility is used to provide a spectrum of active and passive control, allowing the creature to sometimes prescribe its shape changes and at other times extract energy from the fluid. This mix is particularly important in the moderate Reynolds number regime, in which wake vortices play an important energetic role. A well-devised control strategy for a bio-inspired vehicle should -- perhaps must --exploit such flexion and energy exchange; as yet, we lack sufficient understanding to develop such a strategy. Therefore, high-fidelity simulation serves a critical role in exploring the basic mechanisms of locomotion and identifying opportunities for efficient control. In this work, I will present several canonical problems that distill fundamental modes of fluid/flexible body mechanics in biological systems, which are analyzed using a dynamically coupled form of the high-resolution vortex particle method. The first system consists of an articulated three-link swimmer, considered in free-swimming as well as in a passive configuration in the wake of an obstacle. The second system consists of flapping of a two-component fin with a torsion spring, which allows a portion of the fin to passively deflect. The third problem involves an articulated jellyfish, in which the active/passive flexibility mix is explored by designation of the individual hinges. Extension of the methodology to three-dimensional problems will also be discussed.

Jeff D. Eldredge is an Assistant Professor in the Mechanical & Aerospace Engineering Department at UCLA, a position he has held since 2003. He received a NSF CAREER Award in 2007 and the Samueli MAE Teaching Award in 2006. His research group is focused on computational studies of bio-inspired locomotion in fluids, transition and turbulence in hypersonic boundary layers, flow-acoustic interaction in passive acoustic liners, and biomedical devices. Prior to arriving at UCLA, Prof. Eldredge was a post-doctoral research associate at Cambridge University. He completed his Ph.D. in Mechanical Engineering in 2001 at Caltech.