title: A displacement-pressure finite element formulation for analyzing the sound transmission in ducted shear flows with finite poroelastic lining.
abstract: In the present work, the propagation of sound in a lined duct containing sheared mean flow is studied. Walls of the duct are acoustically treated with absorbent poroelastic foams. The propagation of elasto-acoustic waves in the liner is described by Biot's model. In the fluid domain, the propagation of sound in a sheared mean flow is governed by the Galbrun's equation. The problem is solved using a mixed displacement-pressure finite element formulation in both domains. A 3D implementation of the model has been performed and is illustrated on axisymmetric examples. Convergence and accuracy of the numerical model are shown for the particular case of the modal propagation in a infinite duct containing a uniform flow. Practical examples concerning the sound attenuation through dissipative silencers are discussed. In particular, effects of the refraction effects in the shear layer as well as the mounting conditions of the foam on the transmission loss are shown. The presence of a perforate screen at the air-porous interface is also considered and included in the model.
authors.affiliation: Universitéde Technologie de Compiègne, Laboratoire Roberval UMR 6253, BP 20529, 60205 Compiègne cedex, France. benoit.nennig@utc.fr
authors.forename: Benoit
authors.initials: B
authors.lastname: Nennig
authors.forename: Mabrouk Ben
authors.initials: MB
authors.lastname: Tahar
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Perrey-Debain
mesh_terms: D000042:Absorption; D000162:Acoustics / Q000295:instrumentation*; D003198:Computer Simulation; D004548:Elasticity; D004867:Equipment Design; D020342:Finite Element Analysis; D008962:Models, Theoretical; D009038:Motion; D009716:Numerical Analysis, Computer-Assisted; D016062:Porosity; D011312:Pressure; D015203:Reproducibility of Results; D012212:Rheology / Q000295:instrumentation*; D013016:Sound; D013499:Surface Properties; D013997:Time Factors