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Modified multi-load method for non-linear source characterization
KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
KTH, Superseded Departments, Aeronautical and Vehicle Engineering.ORCID iD: 0000-0002-8474-8563
2004 (English)In: ICSV11-St Petersburg, 2004Conference paper (Other academic)
Abstract [en]

Linear frequency domain prediction codes are used for calculation of low frequency sound transmission in and sound radiation from IC-engine exhaust systems. To calculate insertion loss of mufflers or the level of radiated sound information about the engine as an acoustic source is needed. The source model used in the low frequency plane wave range is the linear time invariant 1-port model. The acoustic source data is usually obtained from experimental tests where multi-load methods and especially the two-load method are most commonly used. The exhaust pulsations of an IC-engine are of high level, which means that the engine is not a perfectly linear and time invariant source. It is therefore of interest to develop source models and experimental techniques that try to take this non-linearity into account. In this paper a modified version of the two-load method to improve the characterization of the non-linear acoustic 1-port sources has been developed and tested. Simulation results from various source configurations of a simplified IC-engine model were used to validate the method. The influence of parameters controlling the linearity of the system was investigated. The time-variance of the source model was varied and the source characterization quality using the two-load method and the modified two-load method was evaluated.

Place, publisher, year, edition, pages
Keyword [en]
acoustic source, two-load method, one–port, source model, source impedance, source strength, IC-engine, linearity, time-variance
National Category
Fluid Mechanics and Acoustics
URN: urn:nbn:se:kth:diva-62248OAI: diva2:480034
ICSV11, The Eleventh International Congress on Sound and Vibration, St. Petersburg , Russia, July 5-8, 2004

QC 20120126

Available from: 2012-01-18 Created: 2012-01-18 Last updated: 2016-09-05Bibliographically approved

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