Ajet enginehas asound pressure levelof 80dB, as heard from a distance of 50 feet. Aground crewmember is standing 50 feet from a four-engine jet. What SPL reaches her ear when the first engine is turned on? The second, so that two engines are running? The third? Then all four?
The introduction of acoustical energy into the air in the annular bypass passageway results in the generation in that passageway of fan noise which would be created in the bypass duct of a jet engine employing the nozzle assembly being tested under actual operating conditions. A method for ...
摘要: A jet engine with increased level of jet thrust and decreased level of acoustic noises has gas generator with nozzle. Coaxially with the nozzle of jet engine there is additionally installed volumetric resonator with jet nozzle hermetically connected to the body of gas generator....
engine=n.发动机,引擎;机车 engineer=n.工程师,技师 engineering=n.工程,工程学 England=n.英格兰;英国 English=n.英语 a.英国人的 Englishman=n.英国男子 enjoy=vt.享受;欣赏,喜爱 enlarge=vt.扩大,扩展;放大 enormous=a.巨大的,庞大的 enough=a.足够的 ad.足够地 ensure=vt.保证;保护;赋予 enter=vt.走进...
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...
CFD simulations must account for major shifts in air, not only around the plane, but also as it moves through the engine and interacts with fuel. Air-breathing jet engines, as they are called, draw in oxygen to burn fuel as they fly. In a conventional plane, fan blades push the air ...
The forces on the inside of the engine needed to create this jet give a strong thrust on the engine which pushes the craft forwards. 【参考译文】所有喷气发动机都是反应式发动机,通过以相对较高的速度向后喷射流体而产生推力。发动机内部产生这种喷射所需的力会对发动机产生强大的推力,从而推动飞行器向前...
wake above the ground plane. The buoyancy effects are considered to be small relative to the exhaust velocity and therefore are not included. The graphs show jet wake velocity and temperature contours for a representative engine . The results are valid for sea level, static, standard day ...
A fluidic device for reduction of the sound level of the jet engine according to the invention is applied to the nacelle of jet engine2of FIG. 1. This device is arranged, for example, with reference to the more or less cylindrical exterior wall20(exterior hood) of the nacelle and which ...
Turbojet engine noise reduction with mixing nozzle-ejector combinations Several noise suppressors consisting of combinations of mixing nozzles and ejectors were tested on two full-scale turbojet engines- Maxi-mum sound pressure level reductions of 12 decibels and sound power level reductions of 8 decib...