Dr. Amy Lang, University of Alabama, Tuscaloosa, Alabama “Reducing the Drag Over Aircraft by Mimicking the Surface Geometry of Bristled Shark Skin Scales” Category: Aviation: 2007

The issue of reducing drag over solid surfaces in high velocity flows is one that has kept researchers working for years. It is estimated that even a 1% reduction in drag can save an airline company $100,000 to $200,000 and at least 25,000 gallons of fuel per year per aircraft. Worldwide, this 1% reduction could translate to fuel savings of more than $1 billion per year. The resulting reduction in emissions into our air is equally as impressive.

With her Lindbergh Grant, Dr. Lang will determine whether the surface texture on the skin of fast-swimming sharks, potentially capable of bristling their scales when in pursuit of prey, could be mimicked and used to reduce the drag on aircraft. She will perform water tunnel experiments to measure the flow over and within a bristled sharkskin model (2 cm size scales), which achieves similarity with real sharkskin (0.2 mm size scales) by a corresponding scale down in velocity of the experiments. She will also obtain drag measurements over a sharkskin model in a Couette flow facility containing high viscosity oil. Her objective is to reveal the boundary layer control mechanisms of the bristled sharkskin to deduce the means by which sharks minimize their drag. Dr. Lang’s project has the potential to reduce aircraft drag by 30%, once the technology is refined and implemented, greatly reducing the nation’s dependency on fossil fuels, reducing carbon dioxide emissions into the atmosphere, and costs.

Dr. Lang Working in the Lab

Read this Blog Post from Kitplanes Newsline resulting from the talk that Amy Lang gave during Lindbergh Foundation Day at Sun 'n Fun 2010.

From the Final Report

In the final report from her second year of funding, Dr. Lang stated that the results from her study give evidence that the bristled microgeometry of a shark’s skin may indeed increase maneuverability and decreased drag.  She further believes that re-creating bristled sharkskin may be possible for similar results on aircraft, underwater vehicles, and turbomachinery.  However, more technological advances for applying such a surface that is durable and cost-effective will be needed.

Continued Funding

In August 2009, the National Science Foundation gave a research grant of $383,984 for Dr. Lang to continue this research in collaboration with biologists from the University of South Florida and Mote Marine Laboratory.  They are currently studying sharkskin samples to report variation in angle of bristling with body location.  Recent results suggest very high bristling angles on the sides of the body of the shark.  Models are being constructed based on the recent results obtained form the biologists.  They will also provide sharkskin samples for water tunnel testing in summer 2011.

Publicity

Dr. Lang has received considerable publicity as a result of this project, receiving university wide and national/international attention.  She has also become known as an expert in the field relating to how sharks use their skin to swim faster.  Dr. Lang has been asked to provide a chapter for a book on the subject; she has given presentations on this subject at Sun ‘n Fun during Lindbergh Foundation Day in April 2010; as well as at a celebration of Engineers Week at the McWane Science Center in February 2010.  Dr. Lang has also been interviewed for local television programs, an Alabama PBS program entitled, “On the Job,” and for articles in newspapers and magazines.

FMI:  Read the Final Report.

This aviation grant is sponsored by Jeppesen Sanderson, Inc.
A second year of funding for this research has been sponsored through the Aviation Green Investment Program and the Stanford Financial Group.