Impact of vortex recapture in water-walking Microvelia using a physical model and computational fluid dynamics

Microvelia, one of the genus of water striders, locomote on water and land using an alternating tripod gait. During their gait, the middle legs generate a pair of counter-rotating vortices during their power strokes. Further, the hind legs step into these vortices and re-energize them. Using a physical model and Computational Fluid Dynamics (CFD) modeling, we study the interactions of vortices from the middle and hind legs. We also investigated the fluid-structure interaction between the hind leg and the vortex shed from the middle leg. Overall, this study aims to uncover the role of vortex recapture on the kinematics of Microvelia. We systematically studied the effect of stroke amplitude, leg speed, and stroke frequency of the middle and hind legs on the energetics of Microvelia’s interfacial locomotion. In addition to an in-depth understanding of the fluid dynamics involved in the locomotion of these organisms, these results may guide the designs of water-walking micro-robots.