Meeting Abstract

P2.166  Tuesday, Jan. 5  Instantaneous volumetric wake analysis of locomotion in teleost fishes FLAMMANG, B.E.*; LAUDER, G.V.; TROOLIN, D.R.; STRAND, T.; Harvard University; Harvard University; TSI Incorporated; TSI Incorporated bflammang@oeb.harvard.edu

Previous studies of the wake hydrodynamics of fishes have been restricted to two-dimensional digital particle image velocimetry (DPIV) slices by available technology. By comparing multiple slices, previous researchers hypothesized the three-dimensional structure of the vortex wakes produced by swimming fishes. In teleost fishes, such as the bluegill sunfish, the homocercal tail produces a single jet with each lateral pass. Using conventional two-dimensional DPIV, vorticity shed by the homocercal tail was visualized as two counter-rotating vortices which were hypothesized to be part of a three-dimensional rotating ring through which the jet passed. Now, using a volumetric PIV system, we have confirmed that the three-dimensional structure of the vortex ring produced by the homocercal fin is indeed as predicted. In addition, multiple lateral passes of the tail produced a linked chain of vortex rings. Using this volumetric PIV system we were also able to instantaneously capture the three-dimensional wake interactions of the dorsal and anal fins with the caudal fin in both live fishes and robotic analogs.