Experimental investigation of the interplay between the sound field and the flow field in skewed low-pressure axial fans

European Union, Commission Regulation (EU) No 327/2011, Official Journal of the European Union. Beiler, 1996 Zenger, 2017, Acoustic characterization of forward- and backward-skewed axial fans under increased inflow turbulence, AIAA J., 55, 1241, 10.2514/1.J055383 Agboola, 1999, The effects of axial fan noise control by blade sweep on the radial component of velocity Fukano, 2004, Tip clearance noise of axial flow fans operating at design and off-design condition, J. Sound Vib., 275, 1027, 10.1016/S0022-460X(03)00815-0 Krömer, 2018, Investigation of aeroacoustic properties of low-pressure axial fans with different blade stacking, AIAA J., 56, 1507, 10.2514/1.J056324 Wright, 1990, Blade sweep for low speed axial fans, J. Turbomach., 112, 151, 10.1115/1.2927413 Vad, 2008, Aerodynamic effects of blade sweep and skew in low-speed axial flow rotors at the design flow rate: an overview, Proc. IME J. Power Energy, 222, 69, 10.1243/09576509JPE471 Carolus, 1997, Skewed blades in low pressure fans: a survey of noise reduction mechanisms, 47 Carolus, 2013 Hayden, 1977, Some advances in design techniques for low noise operation of propellers and fans Meecham, 1963, On noise produced by boundary-layer turbulence, J. Acoust. Soc. Am., 35, 116, 10.1121/1.1918427 Wagner, 1996 T. F. Brooks, S. D. Pope, M. A. Marcolini, Airfoil Self-noise and Prediction, NASA Reference Publication 1218. Blake, 1986, vol. 2 M. V. Lowson, reportAssessment and Prediction of Wind Turbine Noise, Flow Solutions Report 92/19, ETSU W/13/00284/REP. Sharland, 1964, Sources of noise in axial flow fans, J. Sound Vib., 1, 302, 10.1016/0022-460X(64)90068-9 Amiet, 1976, Noise due to turbulent flow past a trailing edge, J. Sound Vib., 47, 387, 10.1016/0022-460X(76)90948-2 Roger, 2012, Addendum to the back-scattering correction of amiet's trailing-edge noise model, J. Sound Vib., 331, 5383, 10.1016/j.jsv.2012.06.019 Brown, 1977, The use of skewed blades for ship propellers and truck fans, 201 Moreau, 2007, Competing broadband noise mechanisms in low-speed axial fans, AIAA J., 45, 48, 10.2514/1.14583 Krömer, 2018 Giez, 2016, Effect of the edge-and-tip vortex on airfoil selfnoise and turbulence impingement noise Yang, 2007, Optimization design and experimental study of low-pressure axial fan with forward-skewed blades, Int. J. Rotating Mach., 1, 10.1155/2007/85275 Vad, 2007, Aerodynamic effects of forward blade skew in axial flow rotors of controlled vortex design, Proc. IME J. Power Energy, 221, 1011, 10.1243/09576509JPE420 Stütz, 1992 Kwedikha, 2009 Corsini, 2004, Using sweep to extend the stall-free operational range in axial fan rotors, Proc. IME J. Power Energy, 218, 129, 10.1243/095765004323049869 Li, 2007, Experimental research on aerodynamic performance and exit flow field of low pressure axial flow fan with circumferential skewed blades, J. Hydrodyn., 19, 579, 10.1016/S1001-6058(07)60156-5 Paxton, 2003, High efficiency forward swept propellers at low speed Schneider, 2005 E. Kerschen, A. Envia, Noise Generation by a Finite Swept Airfoil, AIAA Paper 83-0768. Zenger, 2015, Influence of inflow turbulence on aeroacoustic noise of low speed axial fans with skewed and unskewed blades Zenger, 2016, Experimental investigation of the noise emission of axial fans under distorted inflow conditions, J. Sound Vib., 383, 124, 10.1016/j.jsv.2016.07.035 2003 Wright, 1976, The acoustic spectrum of axial flow machines, J. Sound Vib., 45, 165, 10.1016/0022-460X(76)90596-4 Cumming, 1972, Highly skewed propellers, 98 Hanson, 1980, Influence of propeller design parameters on far-field harmonic noise in forward flight, AIAA J., 18, 1313, 10.2514/3.50887 Amiet, 1988, Thickness noise of propeller and its relation to blade sweep, J. Fluid Mech., 192, 535, 10.1017/S0022112088001971 Wright, 2010 Kameier, 1997, Experimental study of tip clearance losses and noise in axial turbomachines and their reduction, J. Turbomach., 119, 460, 10.1115/1.2841145 R. Mailach, I. Lehmann, K. Vogeler, Rotating instabilities in an axial compressor originating from the fluctuating blade tip vortex, J. Turbomach. 123 (3). doi:10.1115/1.1370160. Magne, 2015, Subharmonic tonal noise from backflow vortices radiated by a low-speed ring fan in uniform inlet flow, J. Acoust. Soc. Am., 137, 228, 10.1121/1.4904489 Moreau, 2016, Sub-harmonic broadband humps and tip noise in low-speed ring fans, J. Acoust. Soc. Am., 139, 118, 10.1121/1.4939493 Zhu, 2018, Rotating coherent flow structures as a source for narrowband tip clearance noise from axial fans, J. Sound Vib., 417, 198, 10.1016/j.jsv.2017.11.014 Hurault, 2010, Experimental and numerical study of sweep effect on three-dimensional flow downstream of axial flow fans, Flow Meas. Instrum., 21, 155, 10.1016/j.flowmeasinst.2010.02.003 Dixon, 2014 Pfleiderer, 2005 Lakshminarayana, 1996 Peng, 2008 Horlock, 1958 International Organization for Standardization, 2007 Dougherty, 2002, Beamforming in acoustic testing, 62 Michel, 2010, Akustische antennen [acoustic antennas], 365 Dougherty, 2009, Virtual rotating microphone imaging of broadband fan noise Zenger, 2016, Sound source localization on an axial fan at different operating points, Exp. Fluid, 57, 1 Sijtsma, 2007, Clean based on spatial source coherence, Int. J. Aeroacoustics, 4, 357, 10.1260/147547207783359459 Sarradj, 2012, Three-dimensional acoustic source mapping Quayle, 2008, Mitigation of beamforming interference from closed wind tunnels using CLEAN-SC Albrecht, 2003 Zhang, 2010 Dantec Dynamics, 2014 Gallimore, 2002, The use of sweep and dihedral in multistage axial flow compressor blading - part 1: university research and methods development, J. Turbomach., 124, 521, 10.1115/1.1507333 Vad, 2008, Aerodynamic effects of blade sweep and skew in low-speed axial flow rotors at the design flow rate: an overview, Proc. IME J. Power Energy, 222, 69, 10.1243/09576509JPE471 Zhu, 2016 Sturm, 2012, Tonal fan noise of an isolated axial fan rotor due to inhomogeneous coherent structures at the intake Sturm, 2013, Large scale inflow distortions as a source mechanism for discrete frequency sound from isolated axial fans Sanjosé, 2017, RANS based analytical modeling of broadband noise for a low-speed fan