IEVref:801-32-37ID:
Language:enStatus: Obsolete
Term: volume backscattering differential
Synonym1: volume scattering strength
[Preferred]
Synonym2:
Synonym3:
Symbol:
Definition: level in decibels equal to ten times the logarithm to the base ten of the ratio of the backscattering coefficient of the volume to the reference volume backscattering coefficient 4π/r0, where r0 is the reference distance, preferably chosen to be 1 m

Note 1 to entry: Whatever reference coefficient is used, it shall be specified.

Note 2 to entry: The volume scattering differential for a designated direction other than backward is similarly defined.

Note 3 to entry: Otherwise described, the volume backscattering differential is the backscattered sound pressure level that would exist at the reference distance of r0 from the acoustic centre of the volume containing scatterers, minus the sound pressure level of a plane wave incident on the scatterers.

Note 4 to entry: Expressed in letter symbols:

N V = L SC L i =10 log 10 A V /V 4π r 0 2 / V 0 dB=10 log 10 m 4π / r 0 dB MathType@MTEF@5@5@+=feaagCart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbbjxAHXgarqqtubsr4rNCHbGeaGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaqFn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpeWZqaaeqabiGaciGacaqadmaadaqaaqaaaOqaaiaad6eadaWgaaWcbaGaaeODaaqabaGccqGH9aqpcaWGmbWaaSbaaSqaaiaabofacaqGdbaabeaakiabgkHiTiaadYeadaWgaaWcbaGaaeyAaaqabaGccqGH9aqpcaaIXaGaaGimaiaaykW7caqGSbGaae4BaiaabEgadaWgaaWcbaGaaGymaiaaicdaaeqaaOWaaSaaaeaadaWcgaqaaiaadgeadaWgaaWcbaGaaeODaaqabaaakeaacaWGwbaaaaqaamaalyaabaGaaGinaGGaaiab=b8aWjaadkhadaqhaaWcbaGaaGimaaqaaiaaikdaaaaakeaacaWGwbWaaSbaaSqaaiaaicdaaeqaaaaaaaGccaaMe8UaaeizaiaabkeacqGH9aqpcaaIXaGaaGimaiaaykW7caqGSbGaae4BaiaabEgadaWgaaWcbaGaaGymaiaaicdaaeqaaOWaaSaaaeaacaWGTbaabaWaaSGbaeaacaaI0aGae8hWdahabaGaamOCamaaBaaaleaacaaIWaaabeaaaaaaaOGaaGPaVlaaykW7caqGKbGaaeOqaaaa@663B@

where:
NV  is volume backscattering differential or volume scattering strength
LSC  is backscattered sound pressure level at reference distance
Li  is incident sound pressure level
AV  is backscattering cross-section of scatterers in volume V
r0  is reference distance
V 0 = r 0 3 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbbjxAHXgarqqtubsr4rNCHbGe aGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaq Fn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpe WZqaaeqabiGaciGacaqadmaadaqaaqaaaOqaaiaadAfadaWgaaWcba GaaGimaaqabaGccqGH9aqpcaWGYbWaa0baaSqaaiaaicdaaeaacaaI Zaaaaaaa@3ABB@ is reference volume
m = AV /V  is volume backscattering coefficient
4π/ r 0 = 4π r 0 2 / V 0 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbbjxAHXgarqqtubsr4rNCHbGe aGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaq Fn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpe WZqaaeqabiGaciGacaqadmaadaqaaqaaaOqaamaalyaabaGaaGinaG Gaaiab=b8aWbqaaiaadkhadaWgaaWcbaGaaGimaaqabaaaaOGaeyyp a0ZaaSGbaeaacaaI0aGae8hWdaNaamOCamaaDaaaleaacaaIWaaaba GaaGOmaaaaaOqaaiaadAfadaWgaaWcbaGaaGimaaqabaaaaaaa@41C3@ is reference volume backscattering coefficient.


Publication date:1994-07
Source
Replaces:
Internal notes:2016-01-25: Eqn preceding "est le coefficient de réverbération de volume de référence" corrected to remove the superfluous "/". JGO
2016-02-05: Editorial corrections made: "1 metre" replaced by "1 m" for conformity with ISO 80000-1; 2nd sentence in the definition (containing a requirement) transferred to a note to entry, and subsequent notes renumbered; subscript v replaced by V; <i>V</i> added after volume in "... is backscattering cross-section of scatterers in volume" for alignment with the French. Agreement from TC 1 AG received 2016-02-04. JGO
2016-02-10: Subscript V replaced by <i>V</i>. See mails TC 1 AG received 2016-02-08. JGO

2017-06-02: Cleanup - Remove Attached Image 801-32-37.gif
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