Flippers provide lift, reduce drag: humpback whale
The flippers of the humpback whale channel flow and increase aerodynamic efficiency due to tubercles or bumps.
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Flippers on humpback whales (Megaptera novaeangliae) have non-smooth leading edges, yet demonstrate superior fluid dynamics to the characteristically smooth leading edges of our wings, turbines and other kinds of blades. Despite being 40-50 feet long and weighing nearly 80,000 pounds, humpback whales swim in circles tight enough to produce nets of bubbles only five feet across, which corral their shrimp-like prey. The whale’s surprising dexterity is due primarily to its non-conventional flippers, which have large, irregular looking bumps called tubercules across their leading edges. Whereas sheets of water flowing over smooth flippers break up into myriad turbulent vortices as they cross the flipper, sheets of water passing between a humpback’s tubercules maintain even channels of fast-moving water, allowing humpbacks to keep their “grip” on the water at sharper angles and turn tighter corners, even at low speeds.
Wind tunnel tests of model humpback flippers with and without leading-edge tubercules have demonstrated the fluid dynamic improvements tubercules make, such as a staggering 32% reduction in drag, 8% improvement in lift, and a 40% increase in angle of attack over smooth flippers before stalling. A company called WhalePower is applying these lessons to the design of wind turbines and fans of all sorts – industrial ceiling fans and other HVAC systems, computer fans, etc. – to improve their efficiency, safety, and cost-effectiveness.
"The humpback whale Megaptera novaeangliae is exceptional among the baleen whales in its ability to undertake acrobatic underwater maneuvers to catch prey. In order to execute these banking and turning maneuvers, humpback whales utilize extremely mobile flippers. The humpback whale flipper is unique because of the presence of large protuberances or tubercles located on the leading edge which gives this surface a scalloped appearance. We show, through wind tunnel measurements, that the addition of leading-edge tubercles to a scale model of an idealized humpback whale flipper delays the stall angle by approximately 40%, while increasing lift and decreasing drag." (Miklosovic et al. 2004:L39)
Watch Video of Whales' Hunting Technique
Megaptera novaeangliae (Borowski, 1781)
IUCN Red List Status: Least Concern
Habitat(s): Marine Neritic
Some organism data provided by: ITIS: The Integrated Taxonomic Information System
Organism/taxonomy data provided by:
Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist
Application Ideas: More efficient wind turbines, hydroelectric turbines, ceiling fans, airplane wings, underwater vehicles, boat rudder...
Industrial Sector(s) interested in this strategy: Energy, Manufacturing, Aeronautics, Naval ArchitectureTubercle Technology blades - Wind turbine blades, fans, pumps
Fluid Earth's Humpback Whale Fin for surfboards - Surf board fin
Frank E. Fish
Department of Biology, West Chester University