Numerical Modeling of the Performance of Ray Fins in Fish Locomotion

Abstract

This is a review of our recent investigation on the structure versus performance of ray fins via a potential-flow based fluid-structure interaction model. The kinematics and dynamic performance of two structurally idealized fins, a caudal fin and a pectoral fin, are considered. The numerical method includes a boundary-element model of the fluid motion and a fully-nonlinear Euler-Bernoulli beam model of the embedded rays. Using this model we studied thrust generation and propulsion efficiency of the fins at different combinations of parameters. Effects of kinematic as well as structural properties are examined. It has been illustrated that the fish’s capacity to control the motion of each individual ray, as well as the anisotropic deformability of the fins determined by the architecture of the rays (especially the detailed distribution of ray stiffness), are essential to high propulsion performance.