Accession Number : AD0464435


Title :   EROSION AND NOISE ATTENUATION TESTS ON A 50 FT. CHALK TUNNEL USED AS A JET ENGINE NOISE MUFFLER


Corporate Author : AEROPLANE AND ARMAMENT EXPERIMENTAL ESTABLISHMENT BOSCOMBE DOWN (UNITED KINGDOM)


Personal Author(s) : Beeny, M A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/464435.pdf


Report Date : 03 Nov 1964


Pagination or Media Count : 18


Abstract : Tests were made on a small earth tunnel to check its resistance to erosion and to assess the noise reduction that may be expected when such a device is used to muffle the exhaust noise of a jet aircraft. Photographs taken before and after tests with a Hunter aircraft are given, and estimates made of the attenuations due to absorption of sound by the chalk walls, a 30 degree bend, and an exit which directs the efflux up into the air. It is concluded that there will be no serious erosion problems in a chalk tunnel if the gas velocity is less than 800 ft/sec. and that the 50 ft. tunnel gave a maximum of 22 dB attenuation.


Descriptors :   *JET ENGINE NOISE , UNITED KINGDOM , FEASIBILITY STUDIES , SOUND , LIMESTONE , ATTENUATION , NOISE , CALCIUM COMPOUNDS , SORPTION , ACOUSTIC PROPERTIES , GAS FLOW , SUPPRESSORS , UNDERGROUND STRUCTURES , CARBONATES , EXHAUST GASES , FORAMINIFERA , EROSION , CONSTRUCTION


Subject Categories : Acoustics
      Noise Pollution and Control


Distribution Statement : APPROVED FOR PUBLIC RELEASE