An experimental study of the flow-induced noise created by a wall-mounted finite length airfoil

This paper presents the results of an experimental investigation of the sound produced by flow interaction with a wall-mounted finite length airfoil at low-to-moderate Reynolds number. Acoustic measurements have been taken in an anechoic wind tunnel at a range of Reynolds numbers, angles of attack and for a variety of airfoil aspect ratios (airfoil length to chord ratio) with a single microphone and two perpendicular planar microphone arrays. For comparison, measurements have also been taken with a semi-infinite or twodimensional airfoil and a half-span airfoil with tip flow but no boundary layer impingement. The experimental data is used to examine changes in wall-mounted finite airfoil noise production as a function of Reynolds number, angle of attack and airfoil aspect ratio. Additionally, the data gives insight into the airfoil noise generation mechanisms and the influence of flow at the airfoil tip and wall junction on noise production.

[1]  Thomas F. Brooks,et al.  Airfoil self-noise and prediction , 1989 .

[2]  T. Brooks,et al.  Trailing edge noise prediction from measured surface pressures , 1981 .

[3]  Martin R. Fink,et al.  Prediction of Airfoil Tone Frequencies , 1975 .

[4]  Sanjiva K. Lele,et al.  Effects of mean flow convection, quadrupole sources and vortex shedding on airfoil overall sound pressure level , 2013 .

[5]  N. Sandham,et al.  Stability and receptivity characteristics of a laminar separation bubble on an aerofoil , 2010, Journal of Fluid Mechanics.

[6]  R. Simpson,et al.  Time-depeiident and time-averaged turbulence structure near the nose of a wing-body junction , 1990, Journal of Fluid Mechanics.

[7]  M. R. Fink,et al.  Vortex noise of isolated airfoils , 1972 .

[8]  R. E. Longhouse.  Vortex shedding noise of low tip speed, axial flow fans , 1977 .

[9]  M. A. Marcolini,et al.  Airfoil tip vortex formation noise , 1986 .

[10]  Michaela Herr,et al.  Trailing-Edge Noise Data Quality Assessment for CAA Validation , 2010 .

[11]  R. D. Mehta,et al.  Effect of wing nose shape on the flow in a wing/body junction , 1984, The Aeronautical Journal (1968).

[12]  P. Bradshaw,et al.  Momentum transfer in boundary layers , 1977 .

[13]  J. M. Kendall.  Measurements of noise produced by flow past lifting surfaces , 1978 .

[14]  Roger L. Simpson,et al.  Some features of a turbulent wing-body junction vortical flow , 1997 .

[15]  Con J Doolan,et al.  Broadband trailing edge noise from a sharp-edged strut. , 2011, The Journal of the Acoustical Society of America.

[16]  Thomas F. Brooks,et al.  Scaling of airfoil self-noise using measured flow parameters , 1985 .

[17]  Michael S. Howe,et al.  Hydrodynamics and sound , 2006 .

[18]  Laura A. Brooks,et al.  The effect of boundary layer type on trailing edge noise from sharp-edged flat plates at low-to-moderate Reynolds number , 2012 .

[19]  Sp Fiddes,et al.  Laminar Boundary Layer Aeroacoustic Instabilities , 1994 .

[20]  Richard B. Green,et al.  Vortex formation on squared and rounded tip , 2013 .

[21]  H. Arbey,et al.  Noise generated by airfoil profiles placed in a uniform laminar flow , 1983, Journal of Fluid Mechanics.