Title: About the POD application for separating acoustic and turbulent fluctuations from wall pressure synthesised field

Authors: Eric Gaudard; Philippe Druault; Régis Marchiano; François Van Herpe

Addresses: University Pierre et Marie Curie-Paris 6, UMR 7190, Institut Jean Le Rond d'Alembert – Case 162, 4, Place Jussieu, 75252 Paris Cedex 05, France; CNRS, UMR 7190, Institut Jean Le Rond d'Alembert, 75252 Paris Cedex 05, France ' University Pierre et Marie Curie-Paris 6, UMR 7190, Institut Jean Le Rond d'Alembert – Case 162, 4, Place Jussieu, 75252 Paris Cedex 05, France; CNRS, UMR 7190, Institut Jean Le Rond d'Alembert, 75252 Paris Cedex 05, France ' University Pierre et Marie Curie-Paris 6, UMR 7190, Institut Jean Le Rond d'Alembert – Case 162, 4, Place Jussieu, 75252 Paris Cedex 05, France; CNRS, UMR 7190, Institut Jean Le Rond d'Alembert, 75252 Paris Cedex 05, France ' Research Department, Centre Technique de Velizy A, Route de Gisy, 78140 Velizy-Villacoublay, France; PSA Peugeot Citroën, Case Courrier VV1405, Centre Technique de Vélizy A, Route de Gisy, 78140 Velizy-Villacoublay, France

Abstract: A turbulent flow developing over rigid surface generates two types of excitation loadings: a turbulent flow component that directly impacts the plate and an acoustic component that originates in turbulent flow. The analysis of these loadings is of particular interest especially for future noise reduction strategy implementation in an automobile context. To reproduce acoustic and turbulent fields, a synthesis of random pressure field is proposed thanks to Corcos's model and a diffuse acoustic field. One then proposes to evaluate the ability of proper orthogonal decomposition to discriminate both parts of this synthesised field. Such POD application demonstrates that it acts as a filtering technique in the wavenumber space. But in present study, the acoustic component is shared by multiple POD modes, and therefore cannot be extracted directly. It is also emphasised that such application depends on the frequency resolution and the energy repartition of the synthesised field.

Keywords: proper orthogonal decomposition; POD; wall pressure field; wavenumber spectrum analysis; turbulent flow; noise reduction; vehicle noise; automotive noise; filtering; acoustic field.

DOI: 10.1504/IJAD.2014.057805

International Journal of Aerodynamics, 2014 Vol.4 No.1/2, pp.108 - 133

Available online: 12 Jul 2013 *

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