Fluid-Structure Modeling and the Effects of Passively Deforming Fins in Flapping Propulsion Systems

In this study, experimentally measured deformations of an artificial pectoral fin are compared with computational predictions of these deformations using a fluid-structure interaction model. The effects of fin flexibility on thrust generation are then investigated across a range of fin stroke phase offsets, fin position offsets, and flapping frequencies for tandem pectoral fins. Two different fin geometries, one rectangular and one bioinspired, and three fin membrane materials are considered. In addition to the effects of fin membrane stiffness on thrust, the results demonstrate differences between the two fin geometries with higher thrust from the rectangular fins, but greater benefit of lower fin stiffness in the bioinspired fins. This study continues to build a foundation for the development of an improved analytical tool for flapping fin and vehicle design.