Studying the bumpy protrusions on the fins of humpback whales has already led to more efficient wind and tidal power turbines and now nature is once again the source of inspiration for a new and more efficient hydroelectric turbine.
The latest source of biomimicry is the basking shark, which industrial design student Anthony Reale has borrowed from the create “strait power,” a water-powered turbine generator that tests have shown is 40 percent more efficient than current designs.
Despite being the second largest shark in the ocean, the basking shark is generally considered harmless to humans as it is a filter feeder. It swims with its mouth open to sift zooplankton, small fish and invertebrates from the water before the water is expelled through extended gill slits that nearly encircle its whole head. Although this flow of water assists in the shark’s swimming, Reale recognized that the shape of the shark’s body also played an important role.
With the basking shark’s jaw able to stretch up to 1.2 meter (3.9 ft) in width, a pressure differential is created as the shark swims. As with the wings of an airplane, the water pressure is greater along the straight bottom, while the curved surface of the shark’s body increases the distance the water has to travel, resulting in lower pressure across the shark’s top.
This pressure differential helps draw the water out of the basking shark’s gills and allows the basking shark to be only filter feeder shark that relies solely on the passive flow of water through its pharynx to feed. Other filter feeder sharks, the whale shark and megamouth shark, assist the process by suction or actively pumping water into their pharynxes.
With this in mind, Reale designed his ‘Strait Power’ turbine with a double converging nozzle or an opening within an opening. The water enters the turbine through the first opening and the second nozzle – like the shark’s gills – compresses the water and creates a low-pressure zone to draw the water through and generate more energy.