Meeting Abstract
Studying movement in squids is challenging because they rely on the coordinated interplay between complex fin motions and a pulsed rotatable jet to locomote, and they are capable of swimming effectively in both arms-first and tail-first orientations. Understanding how this dual mode, i.e., jet and fins, system operates during locomotion requires (1) a full 3D platform for quantifying flows from the multiple propulsors/control surfaces and the corresponding body kinematics and (2) mathematical approaches for identifying and categorizing behavioral and hydrodynamic patterns of movements. Therefore, we are using defocusing digital particle tracking velocimetry to quantify 3D flows and high-speed videography to track 3D body motions while squid swim in water tunnels. Proper orthogonal decomposition and topological analysis utilizing critical point properties are also being performed on the 3D kinematic and 3D flow data, respectively, to quantitatively identify and categorize locomotive patterns and highlight essential elements of the swimming kinematics and flow hydrodynamics. Our results show that both the jet and fins contribute to propulsion to varying degrees depending on swimming orientation and behavior, though the jet often produces the most impulse, and isolated and interconnected vortex rings are prominent wake features. In general, the fins produce more complex wake patterns, more multifaceted kinematic fin modes with prominent flapping and traveling wave features, and greater impulse during arms-first than tail-first swimming. While critical point analyses are ongoing, early results indicate that this method has great promise for quantitatively identifying groups of wake features with similar performance benefits.
