Interest in developing alternative energy sources is driving the consideration of a promising technology that uses underwater turbines to convert ocean tidal flow energy into electricity.
Now lessons learned from the ocean's largest mammals has inspired United States Naval Academy researchers to tackle one of the serious challenges of this technology: the low velocity associated with many tidal flows and the difficulty of extracting useful energy from low speed flows using current designs. They will present their findings November 22 at the American Physical Society’s Division of Fluid Dynamics (DFD) meeting in Long Beach, Calif.
“We designed a novel blade modification for potential turbine performance improvement, which was inspired by humpback whale flippers, with the addition of tubercles, or bumps, to the leading edge of each blade,” explains Mark Murray, a Naval Academy engineering professor. Previous research demonstrated the addition of biomimetically derived protuberances (technology that mimics nature) improved stall characteristics and aerodynamic performance.”
The researchers’ modified blades proved to be more effective in extracting energy at low speeds. Importantly, the blades did not degrade performance at high flow speeds or increase the mechanical complexity of the turbine.
Applications of this research may include the development of turbine designs that are more effective in converting low velocity tidal flow energy into useful electricity and more economically feasible to deploy.
This project was conducted as an undergraduate independent research study by Ensign Timothy Gruber, who is currently attending Massachusetts Institute of Technology’s masters program, with Murray and associate professor David Fredriksson in the Naval Architecture and Ocean Engineering Department acting as his faculty advisors.