Waggling wings and micro air jets could cut aircraft emissions by a fifth, discover UK research scientists
Wed 27 May 2009 – Redirecting air flow sideways across an aircraft’s wings causing them to oscillate could dramatically cut airline fuel costs and CO2 emissions by 20%, according to research funded by the Engineering and Physical Sciences Research Council (EPSRC) and Airbus in the UK. The approach uses many thousands of tiny air powered jets which redirect the air, making it flow sideways back and forth over the wing, severely reducing mid-flight drag. The research is still at concept stage but it is hoped to trial the wing technology as early as 2012.
The air powered jets work by the Helmholtz resonance principle – when air is forced into a cavity the pressure increases, which forces air out and sucks it back in again, causing an oscillation – the same phenomenon that happens when blowing over a bottle.
Dr Duncan Lockerby from the University of Warwick, who is leading the project, said: “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.
“The truth is we’re not exactly sure why this technology reduces drag but with the pressure of climate change we can’t afford to wait around to find out. So we are pushing ahead with prototypes and have a separate three-year project to look more carefully at the physics behind it.”
Engineers have known for some time that tiny ridges known as riblets – similar to those found on sharks – can reduce skin-friction drag, a major portion of mid-flight drag, by around 5%. Dr Lockerby and his colleagues believe the micro-jet system could reduce skin-friction drag by up to 40%.
Simon Crook, EPSRC Senior Manager for Aerospace & Defence, said: “This could drastically reduce the environmental cost of flying. Research like this highlights the way UK scientists and engineers continue to make significant contributions to our lives.”
Research on the project is also being carried out at Cardiff, Imperial, Sheffield and Queen’s University, Belfast. EPSRC is the UK’s main agency for funding research in engineering and the physical sciences, investing in more than £740 million ($1.18bn) in research and postgraduate training.