On compressibility assumptions in aeroacoustic integrals: a numerical study with subsonic mixing layers
TypeArticles dans des revues avec comité de lecture
Two assumptions commonly made in predictions based on Lighthill’s formalism are investigated: a constant density in the quadrupole expression, and the evaluation of the source quantity from incompressible simulations. Numerical predictions of the acoustic field are conducted in the case of a subsonic spatially evolving two-dimensional mixing layer at Re = 400. Published results of the direct noise computation (DNC) of the flow are use as reference and input for hybrid approaches before the assumptions on density are progressively introduced. Divergence free velocity fields are obtained from an incompressible simulation of the same flow case, exhibiting the same hydrodynamic field as the DNC. Fair comparisons of the hybrid predictions with the reference acoustic field valid both assumptions in the source region for the tested values of the Mach number. However, in the observer region, the inclusion of flow effects in the Lighthill source term is not preserved, which is illustrated through a comparison with the Kirchhoff wave-extrapolation formalism, and with the use of a convected Green function in the integration process.
Files in this item
Showing items related by title, author, creator and subject.
CHICHEPORTICHE, Jérémie; GLOERFELT, Xavier (Elsevier, 2012)Overset strategy can be an efficient way to keep high-accuracy discretization by decomposing a complex geometry in topologically simple subdomains. Apart from the grid assembly algorithm, the key point of overset technique ...
SONG, Ge; ALIZARD, Frédéric; ROBINET, Jean-Christophe; GLOERFELT, Xavier (AIP Publishing, 2013)It is now well established that linear and nonlinear instability waves play a significant role in the noise generation process for a wide variety of shear flows such as jets or mixing layers. In that context, the problem ...
Comparison of Subgrid-scale Viscosity Models and Selective Filtering Strategy for Large-eddy Simulations AUBARD, Guillaume; STEFANIN VOLPIANI, Pedro; GLOERFELT, Xavier; ROBINET, Jean-Christophe (Springer, 2013)Explicitly filtered large-eddy simulations (LES), combining high-accuracy schemes with the use of a selective filtering without adding an explicit subgrid-scales (SGS) model, are carried out for the Taylor-Green-vortex and ...
ALIZARD, Frédéric; ROBINET, Jean-Christophe; GLOERFELT, Xavier (Elsevier, 2012)This work is dedicated to the presentation of a matrix-free method for global linear stability analysis in geometries composed of multi-connected rectangular subdomains. An Arnoldi technique using snapshots in subdomains ...
Investigation of flow structures involved in sound generation by two- and three-dimensional cavity flows DRUAULT, Philippe; GLOERFELT, Xavier; MERVANT, Thomas (Elsevier, 2011)Proper Orthogonal Decomposition and Stochastic Estimation are combined to shed some light on the link between organized flow structures and noise generation by turbulent flows. Proper Orthogonal Decomposition (POD) is ...