Overview
- University of California, Riverside engineers built a silicone robotic fin and used a large water tunnel to measure lift across ray-like swimming modes.
- Close to the bottom surface, oscillatory flapping generated negative lift that pulled the swimmer downward, the opposite of the positive ground effect seen with steady wings.
- Tilting the fin upward by only a few degrees eliminated the negative lift, aligning with the slight nose-up posture observed in real rays.
- Simulations and release tests found undulatory, wave-like motion maintained ground clearance longer than flapping, which led to quicker seabed contact.
- The peer-reviewed study by Zhu et al. appears in the Journal of the Royal Society Interface, with collaborators from UVA, Lehigh, and Iowa State, and the team says the insights could guide ray-inspired robots for safer near-bottom operations.