US laboratory to present progress on reducing the noise of military jet aircraft
16 August 2012
The University of Cincinnati’s Gas Dynamics and Propulsion Laboratory will demonstrate progress towards reducing the intense noise of supersonic jets, at a forthcoming conference.
The research, by Jeff Kastner, a research professor in the University of Cincinnati's (UC's) College of Engineering and Applied Science (CEAS), will be presented on August 21 at INTER-NOISE 2012, the 41st International Congress and Exposition on Noise Control Engineering, in New York City. Kastner will present on UC discoveries that use chevrons and fluidic injection to reduce supersonic jet noise.
Kastner’s research, supported by funding from the Office of Naval Research, is examining chevron technology developed at UC that has, in part, been commonly used in the commercial aviation industry to reduce noise on jet engines.
Chevrons – serrations on the exhaust side of a jet engine – are becoming more popular in commercial aircraft. They control the turbulence and resulting noise coming from the high-speed flow as it exhausts from the jet engine.
Kastner says the velocities of exotic military aircraft are much higher than commercial aircraft, which is the main reason they’re so much louder. Since chevrons can result in some fuel loss when controlling turbulence, Kastner’s research is testing fluidic technology to enhance the performance of chevrons for high-power military jets. He explains that since the aircraft only need the noise reduction during takeoff, his lab is exploring a chevron/fluidic injection system that can be turned on during takeoff and turned off when the aircraft is in the air, eliminating fuel loss.
Kastner says he and fellow researchers in UC’s Gas Dynamics and Propulsion Laboratory are testing multiple concepts that manipulate the turbulence in the jet exhaust to examine how those changes impact the sound field. That’s because noise is a byproduct of the turbulence, and so manipulating the turbulence can make it less efficient at producing noise.
The short-term goal of the UC research is to reduce noise by 3dBA while ultimately reducing noise 10dBA or more.