Vortex patterns in the wake of pitching, heaving, and combined motion bio-inspired pitching panels

An understanding of how bio-inspired motion interacts with a surrounding fluid environment provides a foundation to supplement a lack of sensory data and learned intuitive motion in synthetic underwater vehicles. Prior work within our research group has focused primarily on the wake dynamics and propulsive performance of isolated, purely pitching propulsors with bio-inspired planforms. The current work builds upon prior results by experimentally investigating pure heaving motions and combined pitching and heaving motions for a series of bio-inspired fin planform geometries. Stereoscopic particle image velocimetry collected in the midspan at a Strouhal number of 0.3 is used to explore the time-varying behaviors of wake vortices. The current work investigates the influence of both propulsor planform and kinematics on wake dynamics, and how that corresponds to what is known in the literature about the timing and magnitude of the circulatory and added-mass contributions to the thrust force and propulsive efficiency.