A jet engine adapted for reducing far-field noise levels is disclosed. The jet engine has a plurality of flap assemblies that are disposed around a perimeter of an exhaust port of the jet engine. Each flap assembly is movable between a first position and a second position. The jet engine ...
The subjective response of humans to jet noises was studied to determine the relative difference in subjective annoyance levels produced by different jet engine configurations. The noises studied were representative of jet airplane ground and fly‐over operations. Further testing was carried out to deter...
In this paper, the authors describe an innovative jet engine noise measurement and prediction tool. The tool measures sound-pressure levels and frequency spectra in the far field. In addition, the tool provides predicted results while the measurements are being made. The predictions are based on ...
Turbofan engine noise mitigation For numerous applications, mitigation of ducted fan noise emission is a major design challenge, particularly in the context of aircraft propulsion, where certification standards have become more stringent over the last decades to support sustainable mobility solutions that ...
noisejetwakeengine喷气发动机 6.0 JET ENGINE WAKE AND NOISE DATA 6.1 Jet Engine Exhaust Velocities and Temperatures 6.2 Airport and Community Noise D6-58326-1 DECEMBER 2002 139 6.0 JET ENGINE WAKE AND NOISE DATA 6.1 Jet Engine Exhaust Velocities and Temperatures This section shows exhaust velocity ...
noise maxima, which can create local noise peaks, even at lower power settings. The innovation proposed is to operate different engines on the aircraft at different power settings to avoid these peaks, whilst still maintaining overall thrust levels demanded. This would have particular application on...
A jet engine has a noise reduction system which reduces the boundary layer located on the outer surface of the nacelle. The noise reduction system includes a plurality of openings located in the outer surface of the nacelle which are in communication with a source of low pressure. The low pre...
RAPID TRANSIT NOISE IS A VALID IRRITANT TO PASSENGERS IN THE CARS AND RESIDENTS ADJACENT TO THE RIGHT-OF-WAY OF THE RAPID TRANSIT SYSTEM. THE LABORATORY AN... V Salmon,SK Oleson 被引量: 1发表: 1966年 ACTIVE CONTROL OF EXHAUST NOISE FROM MILITARY JET ENGINE TEST FACILITIES Active control ...
When the first engine is turned on, the SPL is 80 dB, provided there is no other comparable noise in the vicinity. To determine, fromFigure 23-3, what the SPL is when the second engine is turned on, we note that the difference between the two engine intensity levels is ...
The Shanghai team investigated issues such as shear layer instability, flow field and far field noise. What they came up with is a jet engine treatment called wavy inner wall (WIW) in which they replaced the smooth inner wall found by the exit of the nozzle with walls containing wavy patte...