Applied Acoustics 74 (2013) 1499–1510
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Transmission loss analysis of single-inlet/double-outlet (SIDO) and double-inlet/single-outlet (DISO) circular chamber mufﬂers by using Green’s function method
Subhabrata Banerjee, Anthony M. Jacobi ⇑
Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, IL-61801, USA
a r t i c l e
i n f o
Received 31 July 2012
Received in revised form 6 June 2013
Accepted 17 June 2013
a b s t r a c t
A Green’s function solution method is implemented to study sound attenuation in single-inlet/ double-outlet (SIDO) and double-inlet/single-outlet (DISO) circular chamber mufﬂers. The mufﬂers are modeled as piston driven rigid circular chambers containing a stationary ﬂuid. The pistons are assumed to perform simple harmonic motion with uniform velocities. Velocity potential in the chamber is derived as a superposition of three dimensional velocity potential due to each piston. Pressure ﬁeld in the chamber is calculated from the velocity potential through conservation of linear momentum equation. Acoustic pressure acting on each piston is calculated by averaging over the surface of the piston. Transmission loss (TL) is evaluated from incident and transmitted acoustic energy. TL curves for various inlet/outlet orientations derived from this method is validated with results obtained from the literature. The effect of locations of inlet/outlet on TL is studied.
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Expansion chamber mufﬂers are widely used in automotive systems, HVAC ducts, reciprocating compressors and in other industrial systems. Sound attenuation in such mufﬂers is strongly dependent on geometry as well as on the orientation of inlet/outlet ports. In order to understand these effects, a number of analytical and numerical works has been reported in the literature. The simplest analytical method assumes plane wave propagation in the mufﬂer. Based on this assumption, a four-pole parameter (transfer matrix) which maps upstream condition to downstream condition is derived. Munjal [1–3] discussed the basic concepts of four-pole parameters and derived them for different mufﬂer conﬁgurations with rigid-wall boundary conditions. Plane wave analysis yields results only for acoustically long chamber mufﬂers below the cutoff frequency of higher order modes. In acoustically short chamber mufﬂers, higher order modes are not completely suppressed as they propagate along the chamber, and they inﬂuence the propagation characteristics. In order to overcome the limitations of plane wave analysis, Ih and Lee  derived four-pole parameter for a circular chamber with end inlet/outlet, accounting for higher order mode effects by assuming uniform velocity piston sources. The three dimensional acoustic ﬁeld in the chamber was expressed as ⇑ Corresponding author. Tel.: +1 217 333 4108; fax: +1 217 244 6534. E-mail addresses: email@example.com (S. Banerjee), firstname.lastname@example.org (A.M. Jacobi).
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an inﬁnite summation of rigid body modes (eigenfunctions). Yi and Lee [5,6] obtained four-pole parameters of a circular expansion chamber with side-inlet/outlet based on uniform velocity piston driven model. Experimental validation of the model for different inlet/outlet locations established the effectiveness of the model. Selamet et al. [7–9] developed a three dimensional mode matching technique to study the attenuation for various inlet/outlet conditions in a circular chamber mufﬂer. Similar to prior work , acoustic ﬁeld was expressed as a linear combination of eigenfunctions for a rigid cylinder. Using...
References: international congress on sound and vibration, Stockholm, Sweden. 7–10
July, 2003, 3287–3294.
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