Breaking the Mold: A New Way to School

A fish can improve its efficiency by swimming near other fish. Studying how neighbor-proximity affects performance leads to a better understanding of fish schools and robot swarms. Due to experimental limitations, vertical offsets between fish neighbors (i.e. offsets along the dorsoventral axis) have received less attention. If the vertically-separated foils are actuated in-phase, they can be placed on the same driveshaft, but out-of-phase actuations are more challenging to reproduce. We present here a new setup that uses horizontal airfoils to enable multi-hydrofoil, vertically separated, out-of-phase motions. We present preliminary force data, optimization tests, and particle image velocimetry (PIV) obtained with our new setup. We compare our results with vertically-separated, in-phase foils actuated with a single driveshaft (Re = 10k – 30k).