Search results
Results from the WOW.Com Content Network
This type of noise increases with aircraft speed and also at low altitudes due to the density of the air. Jet-powered aircraft create intense noise from aerodynamics. Low-flying, high-speed military aircraft produce especially loud aerodynamic noise. The shape of the nose, windshield or canopy of an aircraft affects the sound produced. Much of ...
Detailed information on measurement of aircraft acoustic signature to meet the requirements of Annex 16 is found in ICAO Document 9501 [5] and IEC 61265. [6] Data acquisition in one-third-octave bands is required, followed by processing to yield a logarithmically-scaled value in decibels relative to a sound pressure of 20 micropascals for each one-third-octave band.
When sound levels reach a high enough intensity, the sound, whether it is wanted or unwanted, may be damaging to hearing. [3] Environmental noise monitoring is the measurement of noise in an outdoor environment caused by transport (e.g. motor vehicles, aircraft, and trains), industry (e.g. machines) and recreational activities (e.g. music).
Landing quota count values are based on the certificated approach noise level at maximum landing weight minus 9.0 EPNdB. Aircraft were originally divided into six QC bands from 0.5 to 16, but following a review by the Department for Transport [ 1 ] a seventh category – Quota Count 0.25 – was added in March 2007 [ 2 ] and an eighth category ...
The primary sources of jet noise for a high-speed air jet (meaning when the exhaust velocity exceeds about 100 m/s; 360 km/h; 225 mph) are "jet mixing noise" and, for supersonic flow, shock associated noise. Acoustic sources within the "jet pipe" also contribute to the noise, mainly at lower speeds, which include combustion noise, and sounds ...
Level sensors detect the level of liquids and other fluids and fluidized solids, including slurries, granular materials, and powders that exhibit an upper free surface. Substances that flow become essentially horizontal in their containers (or other physical boundaries) because of gravity whereas most bulk solids pile at an angle of repose to a ...
Rolls-Royce Conway Mk508 (1959) with hush kit attached. The most common form of hush kit is a multi-lobe exhaust mixer.This device is fitted to the rear of the engine and mixes the jet core's exhaust gases with the surrounding air and a small amount of available bypass air.
A noise dosimeter (American) or noise dosemeter (British) is a specialized sound level meter intended specifically to measure the noise exposure of a person integrated over a period of time; usually to comply with Health and Safety regulations such as the Occupational Safety and Health (OSHA) 29 CFR 1910.95 Occupational Noise Exposure Standard ...