Friday, June 5, 2009

Cutting Aviation Emissions with ‘Bottletop Technology’

Most of the time we ignore simple solutions dismissing them as too simplistic. But often we can achieve immeasurable amount of success w... thumbnail 1 summary

6:56 PM

Most of the time we ignore simple solutions dismissing them as too simplistic. But often we can achieve immeasurable amount of success with simple and practical solutions. We might think about the shape of wings and speed of airplanes but we don’t give much thought to an airplane’s wings in terms of reducing fuel and carbon emissions by making changes to those wings. But someone was looking at airplane’s wings and thinking of clean and green energy. If we make tiny holes in plane’s wing they can reduce airline fuel intake by up to 40 per cent. A team of British scientists are relying upon the same principle that applies when you blow across the top of a bottle to make a sound.

Dr Duncan Lockerby who is associated with the University of Warwick and also the project leader, explained that placing tens or even hundreds of thousands of tiny holes on the surface of a plane’s wing should considerably diminish mid-flight haul. This will lead towards the reduction of fuel bills and carbon emissions by up to 20 per cent. It seemed that the team had accidentally chanced upon this experiment. According to Dr Duncan Lockerby, “This has come as a bit of a surprise to all of us in the aerodynamics community. It was discovered, essentially, by waggling a piece of wing from side to side in a wind tunnel.” Others are in agreement with what British scientists are implementing in their project. Simon Crook, who is a senior manager for aerospace and defense at the Engineering and Physical Sciences Research Council (EPSRC), agreed that the breakthrough could be instrumental in drastically reducing the environmental cost of flying.

Dr Duncan Lockerby elaborates how this is possible. He says, “Around half the drag a plane experiences is the result of skin friction, so anything that reduces that will deliver big savings in fuel use.” He also admitted that the research team was still grappling with the exact phenomenon that how it happens but that early test results from wind tunnels have been encouraging. The team is also preparing prototypes. These prototypes will help the team to have a better understanding of the process. They are making it certain with the help of prototypes that no major structural changes will be required in the aircraft with perforated wings.

Lockerby clarifies that the innovation is based on the Helmholtz resonance principle. According to the Helmholtz resonance principle when air is forced into a cavity, the pressure inside increases. Once the external force that forces the air into the cavity disappears, the higher-pressure air inside will flow out. However, this surge of air flowing out will tend to over-compensate, due to the inertia of the air in the neck, and the cavity will be left at a pressure slightly lower than the outside, causing air to be drawn back in. This process repeats with the magnitude of the pressure changes decreasing each time (Wikipedia) . When we blow over a bottletop the air is forced into a cavity it increases the pressure and force the air out of the space. This whole exercise produces an oscillation. The research team is expecting the same result by piercing the plane’s wings with numerous holes with chambers underneath. They think that an additional layer of air can be created around the wings that limit drag.

Airbus is taking keen interest in the project and expect that the new perforated wings could be ready for trials by 2012. EPSRC is quite hopeful that this technology will not be useful for aircrafts only but it could be successfully applied to reduce the fuels of cars, boats and trains too.