Advanced experimental procedure for in-duct aero-acoustics
2006 (English)In: 13th International Congress on Sound and Vibration 2006, ICSV 2006, 2006, 1185-1192 p.Conference paper (Refereed)
The purpose of this paper is to present a method for characterization of in-duct aero-acoustic sources that can be described as active acoustic two-ports. The method is applied to investigate the sound produced from an orifice plate. The motivation is to obtain better data for the development of improved prediction methods for noise from flow singularities, e.g., in HVAC systems on aircrafts. Most of the earlier works fall into two categories; papers modeling the scattering of acoustic waves and papers modeling the sound generation. Concerning the scattering it is possible to obtain estimates of the low frequency behavior from linear perturbations of the steady state equations for the flow. Concerning the sound generation most of the presented work is experimental and follows a paper by Nelson&Morfey, which present a scaling law procedure for the in-duct sound power based on a dipole model of the source. One limitation with the earlier works is that the sound power only was measured on the downstream side. Also data was only obtained in 1/3-octave bands, by measuring the sound radiated from an open duct termination. Assuming plane waves and linear acoustics the flow duct singularity can be completely modeled as an active 2-port. The experimental determination of its properties is done in a two steps procedure. In the first step the passive data, i.e., the scattering matrix S, is determined using external (independent) sources. In the second step the S matrix is used and the source vector is determined by testing the system with known acoustic terminations.
Place, publisher, year, edition, pages
2006. 1185-1192 p.
, 13th International Congress on Sound and Vibration 2006, ICSV 2006, 2
Experimental determination, Experimental procedure, Linear perturbations, Low frequency behavior, Prediction methods, Scattering matrices, Scattering of acoustic waves, Steady state equation, Acoustic generators, Aeroacoustics, Climate control, Scattering parameters, Ducts
Fluid Mechanics and Acoustics Aerospace Engineering
IdentifiersURN: urn:nbn:se:kth:diva-155001ScopusID: 2-s2.0-84883444559ISBN: 9781627481502OAI: oai:DiVA.org:kth-155001DiVA: diva2:761278
13th International Congress on Sound and Vibration 2006, ICSV 2006, 2 July 2006 through 6 July 2006, Vienna
QC 201411062014-11-062014-10-292014-11-06Bibliographically approved