Abstract
Predicting and controlling noise from a fluid machine
requires a model of the noise sources themselves, i.e.,
acoustic source data. If the source connects weakly to
the surroundings, the standardized free field methods can
be used for the source sound power determination, i.e.,
source characterization. In the duct systems connected to
the fluid machines, the acoustic source interacts
strongly with the system boundaries and the in-duct
source characteristics cannot be described using only the
emitted sound power. The following general problems
exists: The source characteristics are dependent on the
acoustic load and
the sound power is reflected from the duct
discontinuities as well as from the duct terminations,
the sound pressure measurements might be contaminated by
the turbulence in the flow, and above a certain
frequency, i.e., first non-plane wave mode cut-on
frequency, the sound pressure varies over the duct
cross-section and non-plane waves are introduced. For a
number of applications the plane wave range dominates and
the non-plane waves can be neglected. But for machines
connected to large ducts the nonplane wave range is also
important. In this paper, methods to determine the
in-duct acoustic source data including also the non-plane
waves are discussed. The low and high frequency in-duct
characteristics of a test engine exhaust system are
obtained and combined. The combined source data is useful
when designing the components of the exhaust system, for
example
Original language | English |
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Title of host publication | Proceedings of BNAM 2014 |
Place of Publication | Tallinn |
Publisher | Nordic Acoustics Association |
Pages | 528-533 |
ISBN (Print) | 978-87-995400-1-3 |
Publication status | Published - 2014 |
MoE publication type | B3 Non-refereed article in conference proceedings |
Event | Baltic-Nordic Acoustic Meeting, BNAM 2014 - Tallinn, Estonia Duration: 2 Jun 2014 → 4 Jun 2014 |
Conference
Conference | Baltic-Nordic Acoustic Meeting, BNAM 2014 |
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Abbreviated title | BNAM 2014 |
Country/Territory | Estonia |
City | Tallinn |
Period | 2/06/14 → 4/06/14 |
Keywords
- acoustic source
- IC-engine
- exhaust system