Hydrodynamics of High-Speed Leaping Underwater Soft Robots Empowered by Transient Driving Method

Empowered by the combustion-enabled transient driving method (TDM), underwater soft robots exhibit instantaneous high-speed leaps from water, presenting valuable applications in robotic engineering. This study delves into the optimization of hydrodynamics during the high-speed jumping through the water-air interface, aiming to improve the overall performance of the TDM-enabled robots. We developed a Computational Fluid Dynamics (CFD) model to comprehensively investigate the fluid dynamics involved. This model analyzes the flow field induced by the high-speed leaping-out motions of TDM-driven underwater robots, including flow velocity distribution, pressure, turbulence structure, etc. Employing two-phase CFD model coupling with cavitation model and dynamic mesh technology, the CFD model is validated against experimental data, demonstrating satisfactory agreements and effectively improving calculating accuracy. Furthermore, we explore design modifications to improve locomotion performance. This shape optimization boosts locomotion velocity while simultaneously reducing drag resistance (the maximum drag coefficient has decreased 29%.) and turbulent energy dissipation rates (the maximum rate has decreased 26%.). The findings offer valuable insights for advancing the capabilities of underwater soft robots in high-speed cross-phase tasks.