Influence of pressure gradients on wall pressure beneath a turbulent boundary layer
TypeArticles dans des revues avec comité de lecture
This study investigates the effects of a pressure gradient on the wall pressure beneath equilibrium turbulent boundary layers. Excitation of the walls of a vehicle by turbulent boundary layers indeed constitutes a major source of interior noise and it is necessary to take into account the presence of a pressure gradient to represent the effect of the curvature of the walls. With this aim, large-eddy simulations of turbulent boundary layers in the presence of both mild adverse and mild favourable pressure gradients are carried out by solving the compressible Navier–Stokes equations. This method provides both the aeroacoustic contribution and the hydrodynamic wall-pressure fluctuations. A critical comparison with existing databases, including recent measurements, is conducted to assess the influence of a free stream pressure gradient. The analyses of wall-pressure spectral densities show an increase in the low-frequency content from adverse to favourable conditions, yielding higher integrated levels of pressure fluctuations scaled by the wall shear stress. This is accompanied by a steeper decay rate in the medium-frequency portion for adverse pressure gradients. No significant difference is found for the mean convection velocity. Frequency–wavenumber spectra including the subconvective region are presented for the first time in the presence of a pressure gradient. A scaling law for the convective ridge is proposed, and the acoustic domain is captured by the simulations. Direct acoustic emissions have similar features in all gradient cases, even if slightly higher levels are noted for boundary layers subjected to an adverse gradient.
Fichier(s) constituant cette publication
Cette publication figure dans le(s) laboratoire(s) suivant(s)
Visualiser des documents liés par titre, auteur, créateur et sujet.
Fatigue behavior of a structural steel coated with a WC–10Co–4Cr/Colmonoy 88 deposit by HVOF thermal spraying LA BARBERA-SOSA, J.G.; SANTANA, Y.Y.; VILLALOBOS-GUTIERREZ, C.; CHICOT, Didier; LESAGE, J.; DECOOPMAN, Xavier; IOST, Alain; STAIA, M.H.; PUCHI-CABRERA, Eli-Saul (ELSEVIER, 2013)The fatigue behavior of a SAE 4340 steel, coated with a 50% WC–10Co–4Cr/50% Colmonoy 88 deposit, by high velocity oxygen fuel (HVOF) thermal spray, has been investigated. The change in the maximum alternating stress with ...
CHICOT, Didier; PUCHI-CABRERA, Eli-Saul; IOST, Alain; STAIA, M.H; DECOOPMAN, Xavier; ROUDET, F.; LOUIS, G. (Maney, 2013)For describing the indentation size effect (ISE), numerous models, which relate the load or hardness to the indent dimensions, have been proposed. Unfortunately, it is still difficult to associate the different parameters ...
KOSSMAN, Stephania; CHICOT, Didier; DECOOPMAN, Xavier; IOST, Alain; VAN GORP, Adrien; MEILLOT, E.; PUCHI-CABRERA, Eli-Saul; SANTANA, Y.Y.; STAIA, Mariana (Springer, 2014)Nanostructured yttria-stabilized zirconia coatings for applications in high-temperature environments can be deposited by suspension plasma spraying (SPS) techniques. The present research has been conducted in order to study ...
Fatigue behavior of a structural steel coated with a WC–10Co–4Cr/Colmonoy 88 deposit by HVOF thermal spraying LA BARBERA-SOSA, J.G.; SANTANA, Y.Y.; VILLALOBOS-GUTIERREZ, C.; CHICOT, Didier; LESAGE, J.; DECOOPMAN, Xavier; IOST, Alain; STAIA, M.H.; PUCHI-CABRERA, Eli-Saul (Elsevier, 2013)The fatigue behavior of a SAE 4340 steel, coated with a 50% WC–10Co–4Cr/50% Colmonoy 88 deposit, by high velocity oxygen fuel (HVOF) thermal spray, has been investigated. The change in the maximum alternating stress with ...
An analysis of the elastic properties of a porous aluminium oxide ﬁlm by means of indentation techniques HEMMOUCHE, L.; CHICOT, Didier; AMROUCHE, A.; IOST, Alain; BELOUCHRANI, M.A.; DECOOPMAN, Xavier; LOUIS, G.; PUCHI-CABRERA, Eli-Saul (Elsevier, 2013)The elastic modulus of thin ﬁlms can be directly determined by instrumented indentation when the indenter penetration does not exceed a fraction of the ﬁlm thickness, depending on the mechanical properties of both ﬁlm and ...