By Mark Brinkerhoff
brinkerhoff@newsroom.byu.edu
BYU physics professor Scott Sommerfeldt completed a NASA-funded project to reduce the noise of jet engines.
Sommerfeldt and a team of researchers at NASA's Glenn Research Center in Cleveland, Ohio, collected audio samples inside a specially designed echo-less chamber.
To do so, they mounted over 100 loudspeakers and 90 microphones in the noisy interior of a model jet engine.
Sommerfeldt and his research assistant, Laralee Ireland, used a computer system they developed to process and analyze the data.
The objective was to find out how fan noise (the whine of the engine), acoustical waves and interior pressure contribute to engine noise, Ireland said.
Sommerfeldt and his fellow researchers from General Electric Aircraft Engine and Hersch Acoustical Engineering received NASA's 'Turning Goals into Reality' award last year for their efforts.
'What we're trying to do is protect the population from noise hearing damage,' Sommerfeldt said.
Federal Aviation Administration regulations limit how noisy an aircraft can be.
If stricter noise limits are imposed, many engines will be unable to fly and engines will be grounded, he said.
Sommerfeldt said it's a complicated issue.
People can't typically detect minute noise differences, he said.
'The question is, can we demonstrate that we can reduce noise levels enough to make it a worthwhile technology,' he said.
One big issue is the cost, Sommerfeldt said.
Implementing this technology, known as 'active noise control,' would cost the aviation industry millions of dollars, he said.
Sommerfeldt said he hopes their research will not only benefit the industry but also the population in general.
'The objective is ultimately to reduce noise of aircraft landing and taking off,' said Bob Kraft, contract monitor for GE Aircraft Engine. 'We build the aircraft engines and are therefore responsible for the noise they make.'
The researchers expect a moratorium on publishing the results of their data to give American companies a 'competitive economic advantage,' Sommerfeldt said.
Though they've already completed a five-year research project, it's not the end, he said.
'We'll be moving into another phase of testing. I imagine sometime next year,' Sommerfeldt said.