基于单极子假设的波束成形算法作为一种声场可视化技术，在声源识别中得到了广泛应用。但是在实际工程应用中，声源的类型较为复杂，基于单一声源假设的波束成形无法有针对性地识别不同类型的声源。本文提出了一种混合反卷积方法来分离含有单极子和偶极子的组合声源，该方法构造了波束成形输出与实际声源之间的线性方程，通过求解该线性方程，可以将单极子和偶极子从组合声源中提取出来，并通过多组仿真和实验来检验该混合反卷积算法。结果表明此方法确实可以有效地分离组合声源，并且保证了声源强度的准确性，即使在包含多个声源时依然有效。此方法有望应用于航空发动机气动噪声识别，从高速喷流噪声中提取目标源，更好地研究喷流噪声的成分。
As an acoustic field visualization technology, beamforming based on the monopole assumption has been widely applied in identifying acoustic sources. However, in practical engineering applications, complex types of sound sources make it difficult for beamforming based on the single sound source assumption to identify different types of sound sources pertinently. This paper proposes a hybrid deconvolution method to separate the combined sources containing monopoles and dipoles. The approach constructs a linear equation between the beamforming output and the actual sound source distribution, and monopoles and dipoles can be extracted from the combined sources by solving this linear equation. Four simulation cases and three experimental cases are designed to check the hybrid deconvolution algorithm. The combined sources in the experiment are composed of a dipole formed by a cylindrical spoiler and a monopole caused by a speaker. The results indicate that this method can separate the combined sound sources effectively and ensure the accuracy of the sound source strength, despite the multipoles. This method is expected to be applied in aerodynamic noise recognition, extracting target sources from high-speed jet noise, and better studying the composition of jet noise.
[1] BRANDSTEIN M S, ADCOCK J E, SILVERMAN H F. A localization-error-based method for microphone-array design[C]//1996 IEEE International Conference on Acoustics, Speech, and Signal Processing Conference Proceedings. Piscataway:IEEE Press, 1996:901-904.
[2] POURAZARM P, MODARRES-SADEGHI Y, LACKNER M A. Flow-induced instability of wind turbine blades:AIAA-2014-1219[R].Reston:AIAA, 2014.
[3] DVRRWÄCHTER L, KEBLER M, KRÄMER E. Numerical assessment of open-rotor noise shielding with a coupled approach[J].AIAA Journal, 2019, 57(5):1930-1940.
[4] ALLEN C S, BLAKE W K, DOUGHERTY R P, et al. Aeroacoustic measurements[M]. Berlin:Springer-Verlag, 2002.
[5] BROOKS T F, HUMPHREYS W M. A deconvolution approach for the mapping of acoustic sources (DAMAS) determined from phased microphone arrays[J].Journal of Sound and Vibration, 2006, 294(4-5):856-879.
[6] HÖGBOM J A. Aperture synthesis with a non-regular distribution of interferometer baselines[J].Astronomy and Astrophysics Supplement, 1974, 15:417-426.
[7] BROOKS T, HUMPHREYS W. Extension of DAMAS phased array processing for spatial coherence determination (DAMAS-C)[C]//12th AIAA/CEAS Aeroacoustics Conference (27th AIAA Aeroacoustics Conference). Reston:AIAA, 2006.
[8] SIJTSMA P. CLEAN based on spatial source coherence[C]//13th AIAA/CEAS Aeroacoustics Conference (28th AIAA Aeroacoustics Conference). Reston:AIAA, 2007.
[9] BROOKS T, HUMPHREYS W, PLASSMAN G. DAMAS processing for a phased array study in the NASA langley jet noise laboratory[C]//16th AIAA/CEAS Aeroacoustics Conference. Reston:AIAA, 2010.
[10] BROOKS T, HUMPHREYS W. Three-dimensional applications of DAMAS methodology for aeroacoustic noise source definition[C]//11th AIAA/CEAS Aeroacoustics Conference (26th AIAA Aeroacoustics Conference). Reston:AIAA, 2005.
[11] 杨洋, 倪计民, 褚志刚. 基于反卷积DAMAS2波束形成的发动机噪声源识别[J].内燃机工程, 2014, 35(2):59-65. YANG Y, NI J M, CHU Z G. Engine noise source identification based on DAMAS2 beamforming[J].Chinese Internal Combustion Engine Engineering, 2014, 35(2):59-65(in Chinese).
[12] 薛伟诚, 杨兵, 贾少红, 等. 基于DAMAS算法的气动噪声定位研究[J].工程热物理学报, 2015, 36(10):2142-2145. XUE W C, YANG B, JIA S H, et al. Aeroacoustic source localization based on DAMAS algorithm[J].Journal of Engineering Thermophysics, 2015, 36(10):2142-2145(in Chinese).
[13] 魏龙, 秦朝红, 任方, 等. 一种改进的声反卷积相关声源定位方法[J].航空学报, 2019, 40(11):123100. WEI L, QIN Z H, REN F, et al. An improved acoustic deconvolution method for localizing correlated sound sources[J].Acta Aeronautica et Astronautica Sinica, 2019, 40(11):123100(in Chinese).
[14] MA W, LIU X. DAMAS with compression computational grid for acoustic source mapping[J].Journal of Sound and Vibration, 2017, 410:473-484.
[15] JORDAN P, FITZPATRICK J A, VALIōRE J C. Measurement of an aeroacoustic dipole using a linear microphone array[J].The Journal of the Acoustical Society of America, 2002, 111(3):1267-1273.
[16] LIU Y, QUAYLE A R, DOWLING A P, et al. Beamforming correction for dipole measurement using two-dimensional microphone arrays[J].The Journal of the Acoustical Society of America, 2008, 124(1):182-191.
[17] FLEURY V, BULTÉ J. Extension of deconvolution algorithms for the mapping of moving acoustic sources[J].The Journal of the Acoustical Society of America, 2011, 129(3):1417-1428.
[18] SIJTSMA P, OERLEMANS S, HOLTHUSEN H. Location of rotating sources by phased array measurements[C]//7th AIAA/CEAS Aeroacoustics Conference and Exhibit. Reston:AIAA, 2001.
[19] PANNERT W, MAIER C. Rotating beamforming-motion-compensation in the frequency domain and application of high-resolution beamforming algorithms[J].Journal of Sound and Vibration, 2014, 333(7):1899-1912.
[20] TÓTH B, VAD J, KOTÁN G. Comparison of the rotating source identifier and the virtual rotating array method[J].Periodica Polytechnica Mechanical Engineering, 2018, 62(4):261-268.
[21] MA W, BAO H, ZHANG C, et al. Beamforming of phased microphone array for rotating sound source localization[J].Journal of Sound and Vibration, 2020, 467:115064.
[22] MO P X, JIANG W K. A hybrid deconvolution approach to separate static and moving single-tone acoustic sources by phased microphone array measurements[J].Mechanical Systems and Signal Processing, 2017, 84:399-413.
[23] SCHMIDT R, FRANKS R. Multiple source DF signal processing:An experimental system[J].IEEE Transactions on Antennas and Propagation, 1986, 34(3):281-290.
[24] YARDIBI T, LI J, STOICA P, et al. A covariance fitting approach for correlated acoustic source mapping[J].The Journal of the Acoustical Society of America, 2010, 127(5):2920-2931.
[25] SUZUKI T. L1 generalized inverse beam-forming algorithm resolving coherent/incoherent, distributed and multipole sources[J].Journal of Sound and Vibration, 2011, 330(24):5835-5851.
[26] PAN X J, WU H J, JIANG W K. Multipole orthogonal beamforming combined with an inverse method for coexisting multipoles with various radiation patterns[J].Journal of Sound and Vibration, 2019, 463:114979.
[27] MERINO-MARTÍNEZ R, SNELLEN M, SIMONS D G. Functional beamforming applied to imaging of flyover noise on landing aircraft[J].Journal of Aircraft, 2016, 53(6):1830-1843.
[28] WELCH P. The use of fast Fourier transform for the estimation of power spectra:A method based on time averaging over short, modified periodograms[J].IEEE Transactions on Audio and Electroacoustics, 1967, 15(2):70-73.
[29] FEY U, KÖNIG M, ECKELMANN H. A new Strouhal-Reynolds-number relationship for the circular cylinder in the range 47<Re<2×105[J].Physics of Fluids, 1998, 10(7):1547-1549.
CJA