Le Garrec, Thomas (2008) Direct computation of airfoil trailing edge noise with a multi-domain approach. PhD thesis Mécanique, SINUMEF, ENSAM 2008ENAM0021 p.208.

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Abstract

The study of the mechanisms of noise generation by the flow over an airfoil is essential to reduce the airframe noise. A direct aeroacoustic solver has been developed to shed some light on these mechanisms. Low dissipation and low dispersion numerical schemes are designed to preserve the weak acoustic waves. A multi-size mesh multi-time step algorithm has been developed to realize local grid refinements on a structured mesh and to reduce the calculation cost of the direct noise computation. The present solver is used to compute the noise generated by a 2-D NACA0012 airfoil at a low Reynolds number and to study the effect of the angle of attack on both flow and acoustic fields. Furthermore, the presence of the tonal noise from a NACA0012 airfoil at a moderate Reynolds number of 200 000 is investigated. A numerical insight into the effect of the experimental confinement due to the wind tunnel walls is then given for a 3-D NACA0018 airfoil at Reynolds 160 000. Finally, a direct computation of the flow over a 3-D truncated NACA0012 airfoil at a high Reynolds number (2.32 millions) is performed by large eddy simulation. The solution is compared with an experimental database named EXAVAC. The main noise generation echanisms are well reproduced with the multi-domain approach.

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