Controlling Turbulence Reduce Noise

World airlines continue to face pressure to reduce jet noise. Research conducted by a team of researchers from the University of Illinois at Urbana-Champaign to their expectations.

Daniel Bodony, an assistant professor of aerospace engineering at The University of Illinois at Urbana-Champaign.

Daniel Bodony along with Jon Freund and Kim Jeonglae ​​using Ranger supercomputer. This computer simulates the evolution of the sound waves produced by turbulence from jet aircraft engines. They used a numerical technique called the "large eddy simulation".

"We study the jet-controlled and uncontrolled to understand the changes between them," said Bodony last week. Simulations show the amount of turbulence that flows in jet engines and the important is the number of votes is created in the turbulence.

Unfortunately, said Bodony, noise is not generated where you can control directly. According to him, we must add the controls in other places such as the nozzle and the flow, so the sound and then reduced at a point in the jet.

After researching four years, Bodony and his colleagues developed a new technique for controlling (controller) is more optimal. Controller is a Actuafor plasma -like a giant spark plug- developed by colleagues at Ohio State. This device is capable of changing the sound field by injecting heat.

Small, well-timed disturbances added to an uncontrolled Mach 1.3 turbulent jet (left) result in the quieter, controlled jet (right). Though only subtly different, the controlled jet is producing 30 percent less noise as visualized by the black-and-white contours of dilatation, a measure of air's compression rate. The sound-generating turbulence, as indicated by the vorticity, is shown as color.

Computer simulations on Ranger determine the ideal time and strength to reduce the noise from jet engines without significantly changing the power push.

Improvements in the first round showed the potential of jet aircraft noise reduction of up to 3 decibels, equivalent to 30 percent. "We can reduce the noise after a trial and error," said Bodony.

He believes, with further refinement, noise levels will be much reduced. Bodony research was funded NASA, which designed the third-generation aircraft for the future.

Bodony hope the device will enter the market are made in the next 10-15 years. *** [LIVESCIENCE | KORAN TEMPO 3638]