These images show the results of lab tests of simulated engine airflow. For each pair of images, the top was taken with the plasma actuators switched off and the bottom image was taken with them on. A brighter color indicates a higher degree of mixing in the gas flow. |
Technology developed at Ohio State University may bring about quieter jet engines. Researchers created a silencer technology that creates electrical arcs to control turbulence in engine exhaust airflow — the chief cause of engine noise. These silencers, called plasma actuators, could be turned on and off with a flip of a switch.
The most important factor in silencing an aircraft during takeoff, when the jet engine is the loudest, is controlling exhaust airflow,” says Mohammad Samimy, professor of mechanical engineering. By analyzing images of fluid flows, researchers can tune the newly developed plasma actuators to match certain frequencies in the flow and optimize noise reduction.
Also, according to Samimy, plasma actuators that control noise could give military aircraft an additional level of stealth. Pilots could fire the electrical arcs in certain patterns to mix the hot exhaust gas with outside air, reducing the heat signature that shows up on infrared tracking systems.
