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OSU Mechanical & Aerospace Engineering
MAE RESEARCH SEMINAR SERIES
Dr. Donald R. Webster Karen and John Huff School Chair & ProfessorSchool of Civil and Environmental Engineering
Georgia Institute of Technology
Underwater Flight of the Pteropod
Friday, 7 December 2018, ATRC 1021:30 PM – 2:30 PM (refreshments 1:15 PM)
Abstract: A portable tomographic particle image velocimetry (tomo-PIV) system was used to study fluid dynamicsand kinematics of pteropods (aquatic snails nicknamed ‘sea butterflies’) in Antarctica. These pteropods (Limacinahelicina antarctica) swim with a pair of parapodia (or “wings”) via a unique flapping propulsion mechanism thatincorporates similar techniques as observed in small flying insects. The swimming velocity is typically 14 – 30 mm/sfor pteropod size ranging 1.5 – 5 mm, and the pteropod shell pitches forward-and-backward at 1.9 – 3 Hz. It hasbeen shown that pitching motion of the shell effectively positions the parapodia such that they flap downwardsduring both power and recovery strokes. The tomo-PIV measurements reveal the influence of the vortex structurecreated and shed from the parapodia on the generated lift forces. The non-dimensional variables characterizing themotion of swimming pteropods are flapping, translating, and pitching Reynolds numbers (i.e. Ref, ReU, and ReΩ). Theobserved specimens swim within the same optimal Strouhal number range as observed for a broad range of speciesin air and water. Further, we found that the relationship between these Reynolds numbers show an existence of acritical ReΩ, below which pteropods fail to swim successfully.
Bio: Donald Webster, Ph.D., P.E. is the Karen & John Huff School Chair and Professor in the School of Civil &Environmental Engineering (CEE) at the Georgia Institute of Technology in Atlanta, Georgia. Dr. Webster earned aB.S. from the University of California, Davis (1989), and M.S. (1991) and Ph.D. (1994) degrees from the University ofCalifornia, Berkeley. He joined the Georgia Tech faculty in September 1997 after completing a postdoctoral researchappointment at Stanford University and holding a non-tenure-track faculty position at the University of Minnesota.Dr. Webster’s research expertise lies in environmental fluid mechanics focused on the influence of fluid motion andturbulence on biological systems. His contributions have been in three arenas: 1) illuminating the fluid mechanicsprocesses related to sensory biology and biomechanics; 2) developing advanced experimental techniques andfacilities; and 3) translating research results into bio-inspired design. In recognition of these contributions, Dr.Webster is a Sustaining Fellow of the Association for the Sciences of Limnology and Oceanography and has wonnumerous awards including the Class of 1934 Outstanding Innovative Use of Education Technology Award, theEichholz Faculty Teaching Award, and the British Petroleum Junior Faculty Teaching Excellence Award.
Hosted by: Dr. Arvind Santhanakrishnan ([email protected])
