Étude de la pression pariétale et du bruit de couches limites turbulentes avec gradients de pression.

Abstract : The aim of this study is to provide a better understanding of the effects of a pressure gradient on an equilibrium turbulent boundary layer. In particular, the effects on the aerodynamic part and on the turbulent boundary layer noise are studied here. In fact, in the framework of transport industry, boundary layers constitute a fundamental source of aerodynamic noise. A turbulent boundary layer over a wall can provide a direct and an indirect contribution to the noise felt inside a vehicle. The indirect contribution corresponds to the structural excitation of the structure below and the direct contribution consists in the propagation of pressure waves. Wall pressure fluctuations are also responsible for the propagation of pressure waves outside the turbulent boundary layer. In this regard, simulations of turbulent boundary layers in presence of adverse and favorable pressure gradients are carried out using direct noise computation by solving the compressible Navier-Stokes equations. This method provides the direct contribution and the wall pressure fluctuations, which are responsible for the indirect contribution to the aerodynamic noise. Results show that an adverse pressure gradient leads to higher levels of the direct acoustic emission whereas lower levels are obtained in presence of a favorable pressure gradient in comparison to the zero gradient case. The study of the spectra of the wall pressure fluctuations for the different gradients cases we present, yield to the same hierarchy of levels. We further observed that these effects are amplified with the increase in the intensity of the gradient.
Complete list of metadatas

Cited literature [203 references]  Display  Hide  Download

https://pastel.archives-ouvertes.fr/tel-01346573
Contributor : Abes Star <>
Submitted on : Tuesday, July 19, 2016 - 11:39:10 AM
Last modification on : Wednesday, May 29, 2019 - 5:53:27 PM

File

COHEN.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01346573, version 1

Collections

Citation

Elie Cohen. Étude de la pression pariétale et du bruit de couches limites turbulentes avec gradients de pression.. Mécanique des matériaux [physics.class-ph]. Ecole nationale supérieure d'arts et métiers - ENSAM, 2015. Français. ⟨NNT : 2015ENAM0044⟩. ⟨tel-01346573⟩

Share

Metrics

Record views

624

Files downloads

1633