Soft bodied and hardwired: Quantifying biohybrid jellyfish wake hydrodynamic

Energy consumption is a limiting factor for mission duration of ocean monitoring tools. In contrast, Aurelia aurita jellyfish have a cost of transport 97% lower than some underwater vehicles and are adaptable to a wide range of ocean environments. Here, we experimentally investigate jellyfish wake hydrodynamics using 3-dimensional, 3-component, particle image velocimetry. Ocean monitoring tools could utilize live jellyfish as biohybrid robots by equipping them with onboard microelectronic swim controllers providing electrical muscle stimulation. One key question is the effect of electrical stimulation on swimming hydrodynamics, biomechanics, and associated energy consumption. These experiments enable measurements of wake momentum loss spatially across the jellyfish exumbrellar surface, and temporally during the contraction and relaxation phases. Repeating these measurements with natural and electrically stimulated jellyfish allows the comparison of wake energetics and biomechanics of the swimming stroke. While previous work found electrically stimulated jellyfish consume more energy than natural jellyfish, the origin of this energy consumption is not well understood. Suboptimal muscle activation could play a role in reducing energetic efficiency as has been documented in other animals. These measurements inform an analytical model of jellyfish wake dynamics.