Meeting Abstract

S7-1.4  Friday, Jan. 6  Wake signatures formed at intermediate Re regimes: signals of prey, predators, mates or schoolmates. YEN, J.*; WEBSTER, D.; MURPHY, D.; CATTON, K. ; MITTAL, R.; ZHENG, L.; Georgia Tech; Georgia Tech; Georgia Tech; Colorado State University; Johns Hopkins University; Johns Hopkins University

What happens when an aquatic biologist works together with fluid dynamics engineers? Do we lose a bit of our identity or are we enhanced and entranced? For me (JY), it’s been the latter. We’ve been working with planktonic organisms that operate at intermediate Re, some residing mostly in the viscous regime, others mostly in the inertial regime and then those that dip into both. The adaptations to each regime and the dynamics of the behavior when in transition are fascinating. I’d like to share what we’ve learned about jetting copepods, paddling krill and flapping pteropods from investigations of their propulsion kinematics, flow field dynamics and computational fluid dynamic models. While the analyses focus on propulsion, the objective is to understand the wake signatures left by the swimming plankton and their importance as signals sensed by prey, predators, mates or schoolmates. Plankton generate watery signals that can be attenuated by viscosity and confused with small-scale turbulence. Yet messages are created, transmitted, perceived and recognized. These messages guide essential survival tasks of aquatic organisms. At the small-scale where biologically-generated behavior differs from physically-derived flow, we find plankton self-propel themselves, are aware of each other, and evolve in response to the fluid environment in surprising ways.