Bio-inspired Aquatic Propulsion Mechanism Using a Fin with a Variable-Effective-Length Spring

-Development of a Propulsion Mechanism using the Swaying and Yawing Movements of a Fin-

Abstract

Elastic fins may represent a significant advance over traditional screw propellers for the propulsion of underwater vehicle However, the optimum elasticity of the fin is not constant and changes with the required motion and the environment. To address this, we initially developed a fin with a variable-effective-length spring and documented the thrust characteristics given a simple yawing movement of the fin.
In this study, we developed a new propulsion mechanism that allows both swaying and yawing movements of the fin. We evaluated the behavior of the fin and the flow field surrounding the fin.