How to swim in
a perfect fluid
Department of Aerospace and Mechanical Engineering
University of Southern California
Fluid-body coupling plays a crucial role in the
locomotion of aquatic animals. Much attention has been given recently
to understanding how aquatic animals use this coupling to their
advantage, thus achieving impressive maneuvers and hydrodynamic
efficiencies. In this talk, we discuss basic mechanisms by which
idealized bodies swim in a perfect fluid. We do not propose
high-fidelity models of fish. We rather ask what are the minimum
requirements in order for a submerged body to swim. We focus on two
types of locomotion: (i) active locomotion due to controlled body
deformations, and (ii) passive locomotion due to energy harvested from
ambient vorticity. We comment on the stability of motion in unsteady
flows and the role of hydro-dynamic coupling in the motion coordination
of multiple bodies.