6 December 2007
Jaws of victory with shark energy research
Sharks may come to the rescue of humans in the search for greater energy conservation.
“We hope to explain how a shark’s skin controls the boundary layer to decrease drag and swim faster,” said Amy Lang, assistant professor of aerospace engineering and mechanics at the University of Alabama. “If we can successfully show there is a significant effect, future applications to reduce drag of aircraft and underwater vehicles could be possible.”
Sharks like this speedy mako could help with energy conservation.
The project is investigating the boundary layer flow over a surface that mimics the skin of a fast-swimming shark. The boundary layer is the area closest to the surface where viscous conditions cause drag—in this instance, a shark’s skin.
The project findings will allow researchers to explore natural solutions for the reduction of skin friction over solid surfaces, which could result in new innovations and applications concerning energy conservation. This research will not only provide a greater understanding of the evolutionary development of sharks, but it will also investigate methods of flow control and drag reduction that can easily apply to mobile vehicles.
Reducing drag over solid surfaces can save thousands of dollars. For example, a 1% reduction in drag can save an airline up to $200,000 and at least 25,000 gallons of fuel per year per aircraft. The resulting reduction in emissions into the air is equally impressive.
Lang hopes to explain why fast sharks that swim upwards of 60 mph have smaller denticles, or scales, than slower shark species. Sharks with smaller denticles have the ability to stick out their scales when they swim, allowing them to swim faster and creating a unique surface pattern on the skin that results in various mechanisms of boundary layer control.
Lang is researching the project using a water tunnel facility in Hardaway Hall. The water tunnel lab can increase the shark skin geometry by 100 times with a corresponding decrease in flow over the model. This makes the flow over the skin observable, and it allows for the visualization and measurement of flow using modern experimental techniques.
For related information, go to www.isa.org/manufacturing_automation.