  In this paper, we identify optimal swimming strategies for drag-dominated
swimmers with a passive elastic joint. We use resistive force theory (RFT) to
obtain the dynamics of the system. We then use frequency domain analysis to
relate the motion of the passive joint to the motion of the actuated joint. We
couple this analysis with elements of the geometric framework introduced in our
previous work aimed at identifying useful gaits for systems in drag dominated
environments, to identify speed-maximizing and efficiency-maximizing gaits for
drag-dominated swimmers with a passive elastic joint.
