The flights tested several technologies designed to reduce airframe noise
, which is generated by the aircraft's movement through the air, and doesn't include engine noise.
The Acoustic Research Measurement (ARM) flights, which concluded in May, at NASAs Armstrong Flight Research Center in California, tested technology to address airframe noise
, or noise that is produced by non-propulsive parts of the aircraft, during landing.
The strong interactions between the vortex from the upstream flow and the airfoils downstream are one of the most important effects in airframe noise
generation, especially in the aircraft take-off and landing on the ground [2-4].
Zhang, "Control strategies for aircraft airframe noise
reduction," Chinese Journal of Aeronautics, vol.
Fink's method (FNKAFM) is used for airframe noise
For the past years quieter turbofan engines development accentuated the airframe noise
in turn becoming an important noise source in commercial aircrafts.
The physics behind airframe noise
generation is still not fully understood and must be characterized before reduction techniques can be implemented.
Also, operators can keep the aircraft in a clean aerodynamic configuration for as long as possible to reduce airframe noise
. Of course, one of the most popular methods is to regulate and minimize flights of highly populated or sensitive areas.
* flaps and slats have been eliminated-these are a major source of airframe noise
when a plane is landing,
The controls were OK, and a cursory look at the instruments and indicators appeared fine, but there was a slight airframe noise
. It was similar to the noise you hear When the aircraft is in a slight sideslip, or the rudder is out of trim.
The goal was to use the code to help predict helicopter airframe noise
coming from complex parts, such as landing gear, slats, and flaps.
is addressed by tackling landing gears and high-lift devices, and engine noise through its fan component.