In an effort to help lower the cost of pumping fluids through pipelines, U.S. and German scientists have discovered an unlikely solution: adding more turbulence.
By injecting puffs of water into a water pipe, the team completely eliminated turbulence in the pipe.
The research could have huge implications in a wide variety of fields. The most immediate beneficiaries could be water utilities and oil companies, but aerospace and ship engineers could use the method to make vessels more fuel efficient. Cardiologists could even tap the findings to keep arteries clear and save lives.
"There is a way to completely destroy turbulence for a minimal cost in energy," said Tobias Schneider, a scientist from Harvard University and co-author of a study about the research in the current issue of the journal Science. "I hope it has implications in other fields where people want to reduce turbulence."
The idea to eliminate turbulence was somewhat counter intuitive: To destroy turbulence they would add more. The idea was that the two areas of turbulence would annihilate each other.
To test their theory, the scientists pumped in a stream of water into a nearly 20-foot, clear Plexiglas pipe. As turbulence traveled down the pipe, it encountered another area of turbulence, provided by a a jet of water piped in downstream.
The second area of turbulence acted like a wall. When the original area of turbulence struck the second, the two canceled each other out. Instead of a series of localized, chaotic currents, the water became smooth.
Less energy to pump
The benefit of smooth flow is that it requires less energy to pump than chaotic, turbulent water — a lot less energy. Other experiments had previously shown that turbulence could be eliminated, but it took more energy to cancel the turbulence than it saved in pumping costs. The U.S. and German research is the first to show a net savings in energy by canceling turbulence.
The energy savings were significant in even narrow pipes. The bigger and wider the pipe and the faster the flow, the more energy will be saved, said Schneider and Beverley McKeon, a scientist at the California Institute of Technology who wrote an accompanying article in Science. For the large, buried pipes that supply clean drinking water to cities across the world, the energy savings would be huge.
Other beneficiaries
Water utilities could be the first beneficiary of the technology, but they won't be the only industries that could benefit from the research.
Oil and liquefied natural gas companies also pump large amounts of liquids in large pipes over long distances. Eliminating turbulence in oil and liquefied natural gas will help these companies save money, which should lower the price of oil and gas for consumers.
Even cardiologists could be interested in the research, said Schneider. Smoothing out the flow of blood around blocked arteries could reduce the number or severity of heart attacks.
The same research that eliminates turbulence inside a container should also eliminate, or at least reduce, turbulence around containers, said Schneider and McKeon. Ships and aircraft consume huge amounts of energy pushing their way through air and water. If the friction on oil freighters was reduced by 10 percent, an estimated $10 billion in fuel costs could be saved each year (at a cost of $50 per barrel), said McKeon.
"From faucets to intercontinental pipelines, reducing turbulence has a direct impact on economics and energy issues," said McKeon.