Swimming performance of a biomimetic compliant fish-like robot

• Published in: Experiments in fluids 2009-12, Vol.47 (6), p.927-939
• Main Authors: Epps, Brenden P., Valdivia y Alvarado, Pablo, Youcef-Toumi, Kamal, Techet, Alexandra H.
• Format: Article
• Language: English
• Subjects: Applied sciences; Computational fluid dynamics; Computer science; control theory; systems; Control theory. Systems; Digital particle image velocimetry; Engineering; Engineering Fluid Dynamics; Engineering Thermodynamics; Exact sciences and technology; Flapping; Fluid dynamics; Fluid flow; Fluid- and Aerodynamics; Fundamental areas of phenomenology (including applications); Heat and Mass Transfer; Instrumentation for fluid dynamics; Physics; Research Article; Robotics; Robots; Swimming; Vortices; Wakes
• ISSN: 0723-4864; 1432-1114
• DOI: 10.1007/s00348-009-0684-8

Digital particle image velocimetry and fluorescent dye visualization are used to characterize the performance of fish-like swimming robots. During nominal swimming, these robots produce a ‘V’-shaped double wake, with two reverse-Kármán streets in the far wake. The Reynolds number based on swimming speed and body length is approximately 7500, and the Strouhal number based on flapping frequency, flapping amplitude, and swimming speed is 0.86. It is found that swimming speed scales with the strength and geometry of a composite wake , which is constructed by freezing each vortex at the location of its centroid at the time of shedding. Specifically, we find that swimming speed scales linearly with vortex circulation. Also, swimming speed scales linearly with flapping frequency and the width of the composite wake. The thrust produced by the swimming robot is estimated using a simple vortex dynamics model, and we find satisfactory agreement between this estimate and measurements made during static load tests.