The acoustic impedance of a wide side branch orifice: Experimental determination using three-port methodology
2009 (English)In: SAE International Journal of Passenger Cars - Mechanical Systems, ISSN 1946-3995, Vol. 2, no 1, 1330-1338 p.Article in journal (Refereed) Published
The acoustic impedance of a circular, confined, side branch orifice subjected to grazing flow is studied. Two geometries are tested. In both geometries, the side branch dimension is of the same order as that of the main duct. The system is viewed as an acoustic three- port, whose passive properties are described by a system matrix. The impedance is studied with the acoustic field incident at different ports, which is shown to influence the results significantly. When excited from the leading edge or from the side branch, an interaction of the hydrodynamic and acoustic fields is triggered, while excitation from the trailing edge does not trigger such an interaction. For both the resistance and the reactance (here expressed as an end correction) the results vary in the three possible excitation cases. In the quasi-stationary limit the resistance is given by a loss coefficient times the Mach number, and the end correction collapses to a single value. A simple empirical model is presented, based on the results.
Place, publisher, year, edition, pages
2009. Vol. 2, no 1, 1330-1338 p.
Empirical model, Experimental determination, Grazing flows, Leading edge, Loss coefficients, Passive properties, Quasi-stationary, Side branches, Single-value, System matrices, Trailing edges, Acoustic field measurement, Acoustic impedance, Acoustic impedance measurement, Acoustic waves, Mach number, Orifices, Acoustic fields
IdentifiersURN: urn:nbn:se:kth:diva-152373DOI: 10.4271/2009-01-2043ScopusID: 2-s2.0-77953186312OAI: oai:DiVA.org:kth-152373DiVA: diva2:750849
QC 201409302014-09-302014-09-262014-09-30Bibliographically approved