Airfoil noise induced by low-Mach-number flow is usually computed using the hybrid method, in which usually the incompressible Navier–Stokes equations are first solved to obtain the noise source and then acoustic analogy is used to predict the far-field noise. However this method is only suitable for predicting the aerodynamic noise in the long wavelength limit due to the loss of the acoustic component obtained from the incompressible flow simulation. The current paper presents an acoustic pressure correction method to predict the airfoil noise generated from low-Mach-number flow using a combination of acoustic analogy and the boundary element method. In order to validate the present method, the noise radiated from the low-Mach-number flow over an NACA0012 airfoil is predicted. Directivity patterns of the calculated noise at different frequencies have good agreement with those of the analytical solutions of Howe’s trailing-edge model.
PatersonR.VogtP.FinkM.Vortex shedding noise of an isolated airfoil. J. Aircr., 1973, 10(5), 296–302.
2.
TamC. K. W.Discrete tones of isolated airfoils. J. Acoust. Soc. Am., 1974, 55(6), 1173–1177.
3.
AmietR. K.Noise due to turbulent flow past a trailing edge. J. Sound Vib., 1976, 47(3), 387–393.
4.
HoweM. S.A review of the theory of trailing edge noise. J. Sound Vib., 1978, 61(3), 437–465.
5.
HoweM. S.Edge-source acoustic Green’s function for an airfoil of arbitrary chord, with application to trailing-edge noise. Q. J. Mech. Appl. Math., 2001, 54(1), 139–155.
6.
RogerM.MoreauS.Back-scattering correction and further extensions of Amiet’s trailing-edge noise model. Part I: Theory. J. Sound Vib., 2005, 286(3), 477–506.
7.
DesquesnesG.TerracolM.SagautP.Numerical investigation of the tone noise mechanism over laminar airfoils. J. Fluid Mech., 2007, 591, 155–182.
8.
SanbergR. D.JonesL. E.SnadhamN. D.JosephP. F.Direct numerical simulations of tonal noise generated by laminar flow past airfoils. J.Sound Vib., 2009, 320(4, 5), 838–858.
EwertR.SchroderW.On the simulation of trailing edge noise with a hybrid LES/APE method. J. Sound Vib., 2004, 270(3), 509–524.
12.
OberaiA. A.RoknaldinF.HughesT. J. R.Computational procedures for determining structural-acoustic response due to hydrodynamic sources. Comput. Meth. Appl. Mech. Engng, 2000, 190(3–4), 345–361.
13.
OberaiA. A.RoknaldinF.HughesT. J. R.Computation of trailing-edge noise due to turbulent flow over an airfoil. AIAA J., 2002, 40(11), 2206–2216.
14.
Ffowcs WilliamsJ. E.HawkingsD. L.Sound generation by turbulence and surface in arbitrary motion. Philos. Trans. R. Soc., 1969, 264, 321–342.
15.
SingerB. A.BrentnerK. S.LockardD. P.LilleyG. M.Simulation of acoustic scattering from a trailing edge. J. Sound Vib., 2000, 230(3), 541–550.
16.
HoweM. S.Trailing edge noise at low Mach number. J. Sound Vib., 1999, 225(2), 211–238.
17.
SchramC.AnthoineA.HirschbergA.Calculation of sound scattering using Curle’s analogy for noncompact bodies. In Proceedings of the 11th AIAA/CEAS Aeroacoustics ConferenceNo. 2005-2836, Monterey, California 23–25 May2005.
18.
GoldsteinM. E.Aeroacoustics, 1976 (McGraw-Hill International Book Company, New York).
19.
SchramC.A boundary element extension of Curle’s analogy for non-compact geometries at low Mach numbers. J. Sound Vib., 2009, 322(1–2), 264–281.
20.
KhalighiY.ManiA.HamF.MoinP.Prediction of sound generated by complex flows at low Mach numbers. AIAA J., 2010, 48(2), 306–316.
MaZ. H.Handbook of applied mathematics, 2005 (Tsinghua University Press, Beijing).
23.
Fluent Inc. Fluent 6.3 User’s Guide (CD-ROM), 2006 (Fluent Inc., San Diego, California).
24.
YuD. Z.MeiR. W.ShyyW.A multi-block lattice Boltzmann method for viscous fluid flows. Int. J. Num. Meth. Fluids, 2002, 39(2), 99–120.
25.
NakonoT.FujisawaN.OgumaY.TakagiY.LeeS.Experimental study on the flow and noise characteristics of NACA0018 airfoil. J. Wind Engng Ind. Aerodyn., 2007, 95(7), 511–531.
MoreauD. J.BrooksL. A.DoolanC. J.On the aeroacoustic tonal noise generation mechanism of a sharp-edge plate. J. Acoust. Soc. Am., 2011, 129(4), 154–160.
28.
PowellA.Aerodynamic noise and the plane boundary. J. Acoust. Soc. Am., 1960, 32(8), 982–990.
29.
Ffowcs WilliamsJ. E.HallL. H.Aerodynamic sound generation by turbulent flow in the vicinity of a scattering half plane. J. Fluid Mech., 1970, 40, 657–670.
30.
CrightonD. G.LeppingtonF. G.On the scattering of aerodynamic noise. J. Fluid Mech., 1971, 46(3), 577–597.
