Journal of Propulsion Technology ›› 2021, Vol. 42 ›› Issue (1): 10-38.DOI: 10.13675/j.cnki.tjjs.200329
• Aero-thermodynamics • Previous Articles Next Articles
Online:
2021-01-15
Published:
2021-01-15
乔渭阳1,王良锋2,段文华1,赵磊3
基金资助:
QIAO Wei-yang1, WANG Liang-feng2, DUAN Wen-hua1, ZHAO Lei3. Theory, Model and Method of Aero-Engine Aeroacoustic Design[J]. Journal of Propulsion Technology, 2021, 42(1): 10-38.
乔渭阳,王良锋,段文华,赵磊. 航空发动机气动声学设计的理论、模型和方法[J]. 推进技术, 2021, 42(1): 10-38.
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[1] Huff D L. NASA Glenn’s Contributions to Aircraft Engine Noise Research[R]. NASA/TP-2013-217818. [2] Doychak Joseph. Jet Engine Noise Reduction, Department of NAVY Jet Noise Reduction (JNR) Project[R]. Washington: Naval Research Advisory Committee, 2009. [3] Bjorn V S, Albery C B, Shilling R, et al. U.S. Navy Flight Deck Hearing Protection Use Trends: Survey Results[R]. USA: Naval Air Warfare Center Aircraft Div Patuxent River Md, 2006. [4] McKinley R L, Bjorn V S, Hall J A. Improved Hearing Protection for Aviation Personnel[R]. USA: Air Force Research Lab Wright-Patterson Afb Oh, 2005. [5] International Civil Aviation Organization. Annex 16: Environmental Protection Volume I: Aircraft Noise, 5th ed[M]. Montreal: International Civil Aviation Organization, 2008. [6] He Qinxian. Development of an Income-Based Hedonic Monetization Model for the Assessment of Aviation-Related Noise Impacts[D]. Massachusetts: Massachusetts Institute of Technology, 2010. [7] Butcher Louise. Aviation: Noise Pollution[R]. London: House of Common Library, 2014. [8] Lord W K. Aircraft Noise Source Reduction Technology[C]. CA: Airport Noise Symposium Palm Spring, 2004. [9] Envia E. Emerging Community Noise Reduction Approaches[C]. Honolulu: 3rd AIAA Atmospheric Space Environments Conference, 2011. [10] Ihme M. Combustion and Engine-Core Noise[J]. Annual Review of Fluid Mechanics, 2017, 49(1): 277-310. [11] Neise Wolfgang. Engines as Pacemakers for Reduction of Noise and Emission[R]. Berlin: Deutsches Zentrum für Luft-Und Raumfahrt, 2004. [12] Bradley Andrew. An Aero-Engine Vision of 2020[R]. UK: Rolls-Royce plc, 2004. [13] Elliott D. Aircraft Engine Noise Research and Testing at the NASA Glenn Research Center[R]. NASA GRC-E-DAA-TN27736, 2015. [14] Peake N, Parry A B. Modern Challenges Facing Turbomachinery Aeroacoustics[J]. Annual Review of Fluid Mechanics, 2012, 44(1): 227-248. [15] 乔渭阳, 王良锋. 航空发动机气动声学(第二版)[M]. 西安: 西北工业大学出版社, 2016. [16] Lighthill M J. On Sound Generated Aerodynamically, I: General Theory[J]. Proceedings of the Royal Society of London, 1952, (211A): 564-587. [17] Lighthill M J. On Sound Generated Aerodynamically, II: Turbulence as a Source of Sound[J]. Proceedings of the Royal Society of London, 1954, (222A): 1-32. [18] Envia Edmane. Fan Noise Reduction: An Overview[J]. Aeroacoustics, 2002, 1(1): 43-64. [19] Neise Wolfgang, Michel Uif. Turbomachinery Aerodynamics Noise[R]. Berlin: Deutsches Inst. Fuer Luft-Und Raumfahrt, 1994. [20] Nesbitt E. Towards a Quieter Low Pressure Turbine: Design Characteristics and Prediction Needs[J]. International Journal of Aeroacoustics, 2011, 10(1): 1-16 [21] Traub Paul, Grundel Hans, Gautier Sebastien. Numerical Investigation for Optimizing the Aero-Acoustical Design of Modern LP-Turbines[C]. Vienna: The Thirteenth International Congress on Sound and Vibration, 2006. [22] Stone J R, Berton J J, Krejsa E A, et al. Initial Development and Calibration of a Design Guide for Jet Noise Reduction[R]. AIAA 2004-3315. [23] Schnell R, Michel U. Turbomachinery Noise Source CFD Models for Low Noise Aircraft Designs[R]. Berlin: Deutsches Zentrum für Luft-Und Raumfahrt, 2004. [24] Mattingly J D, Heiser W H, Pratt D T. Aircraft Engine Design[R]. Reston: American Institute of Aeronautics and Astronautics, 2002. [25] 航空发动机设计手册总编委员会. 航空发动机设计手册(第5, 8, 9, 10册)[M]. 北京: 航空工业出版社, 2001. [26] Zorumski W E. Aircraft Noise Prediction Program[R]. NASA TM-83199, 1986. [27] Kontos K B, Janardan B A, Gliebe P R. Improved NASA-ANOPP Noise Prediction Computer Code for Advanced Subsonic Propulsion Systems Volume 1: ANOPP Evaluation and Fan Noise Model Improvement[R]. NASA CR-195480, 1996. [28] Hough J W, Weir D S. Aircraft Noise Prediction Program (ANOPP) Fan Noise Prediction for Small Engine[R]. NASA CR-198300, 1996. [29] Rawls J W, Jr. Yeager J C. High Speed Research Noise Prediction Code (HSRNOISE) User’s and Theoretical Manual[R]. NASA CR-2004-213014. [30] Dunn D G, Peart N A. Aircraft Noise Source and Contour Estimation[R]. NASA CR-114649, 1973. [31] Heidmann M F, Feiler C E. Noise Comparisons from Full-Scale Fan Tests at NASA Lewis Research Center[R]. NASA CR-73-1017, 1973. [32] Heidmann M F. Interim Prediction Method for Fan and Compressor Source Noise[R]. NASA TM-X-71763, 1975. [33] Smith M J T, Bushell K W. Turbine Noise-Its Signification in the Civil Aircraft Noise Problem[R]. USA: American Society of Mechanical Engineers, 1969. [34] Krejsa E A, Valerino M F. Interim Prediction for Turbine Noise[R]. NASA TM-X-73566, 1976. [35] Matta R K, Sandusky G T, Doyle V L. GE Core Engine Noise Investigation-Low Emission Engine[R]. AD A048590, 1977. [36] Huff R G, Clark B J, Dorsch R G. Interim Prediction Method for Low Frequency Core Engine Noise[R]. NASA TM-X-71627, 1974. [37] Emmerling J J, Kazin S B, Matta R K. Core Engine Noise Control Program, Vol.III: Prediction Method[R]. AD A030376, 1976. [38] Mathews D C, Rekos N F [39] Ho P Y, Doyle V L. Combustion Noise Prediction Update[R]. AIAA 79-0588. [40] Stone J R, Krejsa E A, Clark B J. Progress in Core/Combustion Noise Prediction[R]. AIAA 2005-1199. [41] Bushell K W. Gas Turbine Jet Noise Exhaust Prediction[R]. USA: Society of Automotive Engineers, 1973. [42] Stone J R. Interim Prediction Method for Jet Noise[R]. NASA TM-X-71618, 1974. [43] Stone J R, Montegani F J. An Improved Prediction Method for the Noise Generated in Flight by Circular Jets[R]. NASA TM-81470, 1980. [44] Harper-Bourne M, Fisher M J. The Noise from Shock Waves in Supersonic Jets[C]. Brussels: AGARD Conference on Noise Mechanisms, 1974. [45] Tanna H K, Dean P D, Burrin R H. The Generation and Radiation of Supersonic Jet Noise-Shock-Associated Noise Data[R]. AFAPL-TR-76-65, 1976. [46] Pao S P. A Correlation of Mixing Noise from Coannular Jets with Inverted Flow Profiles[R]. NASA TP-1301, 1979. [47] Russell J W. A Method for Predicting the Noise Levels of Coannular Jets with Inverted Flow Profiles[R]. NASA CR-3176, 1979. [48] Nesbitt E H, Ganz U W, Diamond J A, et al. An Empirical Prediction of Inlet Radiated Broadband Noise from Full Scale Engines[R]. AIAA 98-0470. [49] Rodrigo C C, Guimar?es, Greco Paulo, et al. Development of Fan Broadband Noise Semi-Empirical Prediction Method Adjustable from Operation Point[R]. AIAA 2012-2268. [50] Krejsa E A, Stone J R. Enhanced Fan Noise Modeling for Turbofan Engines[R]. NASA CR-218421, 2014. [51] Morin B, Atassi O. An Empirical Model for Turbine Noise Prediction[R]. Vancouver: AARC Turbine Noise Workshop, 2008. [52] Hetherington R. Compressor Noise Generated by Fluctuating Lift Resulting from Rotor-Stator Interaction[J]. AIAA Journal, 1963, 1(2): 473-474. [53] Wright S E. The Acoustic Spectrum of Axial Flow Machines[J]. Journal of Sound and Vibration, 1976, 45: 165-223. [54] Lowson M V. Theoretical Studies of Compressor Noise[R]. NASA CR-1278, 1969. [55] Lowson M V. Theoretical Studies of Compressor Noise[J]. The Journal of Acoustical Society of America, 1970, 47: 371-385. [56] Hanson D B. Unified Analysis of Fan Stator Noise[J]. The Journal of Acoustical Society of America, 1973, 54: 1571-1591. [57] Tyler J M, Sofrin T G. Axial Flow Compressor Noise Studies[J]. SAE Transactions, 1962, 52: 309-332. [58] Goldstein M E. Aeroacoustics[M]. New York: McGRAW-HILL, 1976. [59] Kaji S, Okazaki T. Generation of Sound by Rotor-Stator Interaction (Sound Generation by Rotor-Stator Interaction in Subsonic Axial Flow Compressors, Using Acceleration Potential and Wake Technique)[J]. Journal of Sound and Vibration, 1970, 13: 281-307. [60] Whitehead D S. Vibration and sound Generation in a Cascade of Flat Plates in Subsonic Flow (Blade Vibration and Noise Generation in Turbomachines by Calculation of Subsonic Flow Through Flat Plate Cascade)[R]. London: Aeronautical Research Council, 1972. [61] Smith S N. Discrete Frequency Sound Generation in Axial Flow Turbomachines (Calculation of Unsteady, Subsonic Flow Through Infinite, Two-Dimensional Flat Plate Blade)[R]. USA: Ministry of Aviation, 1973. [62] Kaji S, Okazaki T. Propagation of Sound Waves Through a Blade Row: I. Analysis Based on the Semi-Actuator Disk Theory[J]. Journal of Sound and Vibration, 1970, 11(3): 339-353. [63] Kaji S, Okazaki T. Propagation of Sound Waves Through a Blade Row: II. Analysis Based on the Acceleration Potential Method[J]. Journal of Sound and Vibration, 1970, 11(3): 355-375. [64] Osborne C. Compressible Unsteady Interactions Between Blade Rows (Compressibility Effects on Unsteady Forces Generated by Jet Engine Blade Rows Aerodynamic Interference, Considering Potential Flow and Viscous Wake Interactions)[J]. AIAA Journal, 1973, 11: 340-346. [65] Hanson D B. Coupled 2-Dimensional Cascade Theory for Noise and Unsteady Aerodynamics of Blade Row Interaction in Turbofans, Volume1-Theory Development and Parametric Studies[R]. NASA CR-4506, 1994. [66] Namba M. Three-Dimensional Analysis of Blade Force and Sound Generation for An Annular Cascade in Distorted Flows[J]. Journal of Sound and Vibration, 1977, 50(4): 479-508. [67] Kobayashi H. Three-Dimensional Effects on Pure Tone Noise Due to Inflow Distortion[R]. AIAA 78-1120. [68] Ventres C S, Theobald M A, Mark W D. Turbofan Noise Generation[R]. NASA CR-167952, 1982. [69] Meyer H D, Envia E. Aeroacoustic Analysis of Turbofan Noise Generation[R]. NASA CR-4715, 1996. [70] Sharland I J. Sources of Noise in Axial Flow Fans[J]. Journal of Sound and Vibration, 1964, 1(3): 302-322. [71] Mugridge B D. Broadband Noise Generation by Airfoils and Axial Flow Fans[R]. AIAA 73-1081. [72] Morfey C L. Broadband Sound Radiated from Subsonic Rotors[J]. Fluid Mechanics, Acoustics, and Design of Turbomachinery, 1974, 1(1): 461-492. [73] Mani R. Noise Due to Interaction of Inlet Turbulence with Isolated Stators and Rotors[J]. Journal of Sound and Vibration, 1971, 17(2): 251-260. [74] Homicz G F, George A R. Broadband and Discrete Frequency Radiation from Subsonic Rotors[J]. Journal of Sound and Vibration, 1974, 36(2): 151-177. [75] Amiet R K. Acoustic Radiation from an Airfoil in a Turbulent Stream[J]. Journal of Sound and Vibration, 1975, 41(4): 407-420. [76] Paterson R W, Amiet R K. Acoustic Radiation and Surface Pressure Characteristics of an Airfoil Due to Incident Turbulence[R]. NASA CR-2733, 1976. [77] Atassi H M, Hamad G. Sound Generated in a Cascade by Three-Dimensional Disturbances Convected in Subsonic Flow[R]. AIAA 81-2046. [78] Gliebe P R. Fan Broadband Self Noise Prediction Model[R]. AIAA 2002-2490. [79] Glegg S A L. Airfoil Self Noise Generated in a Cascade[R]. AIAA 96-1739. [80] Glegg S A L. Broadband Noise from Ducted Prop Fans[R]. AIAA 93-4402. [81] Gouville Benoit de, Roger M, Cailleau J M. Prediction of Fan Broadband Noise[R]. AIAA 1998-2317. [82] Phillip Joseph, Anthony Parry. Rotor/Wall Boundary-Layer Interaction Broadband Noise in Turbofan Engines[R]. AIAA 2001-2244. [83] Ganz U W, Joppa P D, Patten T J, et al. Boeing 18-inch Fan Rig Broadband Noise Test[R]. NASA CR-1998-208704. [84] Nallasamy M, Envia E. Computation of Rotor Wake Turbulence Noise[J]. Journal of Sound and Vibration, 2005, 282(3-5): 649-678. [85] Koch W. On the Transmission of Sound Waves Through a Blade Row[J]. Journal of Sound and Vibration, 1971, 18(1): 111-128. [86] Glegg S A L. The Response of a Swept Blade Row to a Three-Dimensional Gust[J]. Journal of Sound and Vibration, 1999, 227 (1): 29-64. [87] Donald B. Hanson, Horan Kelly P.. Turbulence/Cascade Interaction-Spectra of Inflow, Response Cascade, And Noise[R]. AIAA 98-2319. [88] Hanson D B. Theory for Broadband Noise of Rotor and Stator Cascades with Inhomogeneous Inflow Turbulence Including Effects of Lean and Sweep[R]. NASA CR-210762, 2001. [89] Evers I, Peake N. On Sound Generation by the Interaction Between Turbulence and a Cascade of Airfoils with Non-Uniform Mean Flow[J]. Journal of Fluid Mechanics, 2002, 463: 25-52. [90] Posson H, Roger M, Moreau S. On a Uniformly Valid Analytical Rectilinear Cascade Response Function[J]. Journal of Fluid Mechanics, 2010, 663: 22-52. [91] Posson H, Moreau S, Roger M. On the Use of a Uniformly Valid Analytical Cascade Response Function for Fan Broadband Noise Predictions[J]. Journal of Sound and Vibration, 2010, 329(18): 3721-3743. [92] Posson H, Moreau S, Roger M. Broadband Noise Prediction of Fan Outlet Guide Vane Using a Cascade Response Function[J]. Journal of Sound and Vibration, 2011, 330: 6153-6183. [93] Posson H, Peake N. The Acoustic Analogy in an Annular Duct with Swirling Mean Flow[J]. Journal of Fluid Mechanics, 2013, 726: 439-475. [94] Masson V, Posson Hélène, Sanjose Marlène, et al. Fan-OGV Interaction Broadband Noise Prediction in a Rigid Annular Duct with Swirling and Sheared Mean Flow[C]. France: 22nd AIAA/CEAS Aeroacoustics Conference,2016. [95] Ju H, Mani R, Vysohlid M, et al. Investigation of Fan-Wake / Outlet-Guide-Vane Interaction Broadband Noise[J]. AIAA Journal, 2015, 53(12): 3534-3550. [96] Ju H. Effects of Vane Sweep on Fan-Wake/Outlet-Guide-Vane Interaction Broadband Noise[C]. France: 22nd AIAA/CEAS Aeroacoustics Conference, 2016. [97] Atassi H M, Ali A A, Atassi O V, et al. Scattering of Incidence Disturbances by an Annular Cascade in a Swirling Flow[J]. Journal of Fluid Mechanics, 2004, 29: 111-138. [98] Atassi H M, Vinogradov I V. A Model for Fan Broadband Interaction Noise in Nonuniform Flow[R]. AIAA 2005-2880. [99] Atassi H M, Vinogradov I V. Modelling Broadband Fan Noise and Comparison with Experiments[R]. AIAA 2007-3691. [100] Atassi H M, Logue M M. Effect of Turbulence Structure on Broadband Fan Noise[R]. AIAA 2008-2842. [101] 赵 磊. 涡轮气动-声学一体化设计理论及方法研究[D]. 西安: 西北工业大学, 2013. [102] 谭洪川, 乔渭阳, 赵 磊. 低压涡轮气动/声学一体化设计方法——总体参数优化[J]. 推进技术, 2012, 33(4): 573-578. [103] Michel U. In-duct Matching Between CFD and CAA[C]. Berlin: TurboNoise CFD Meeting, 2003. [104] Ovenden N C, Rienstra S W. Mode-Matching Streategies in Slowly Varying Engine Ducts[R]. AIAA 2003-3139. [105] Lebrun M, Favre C. Fan-OGV Unsteady Navier-Stokes Computation Using an Adapted Acoustic Mesh[R]. AIAA 2004-2995. [106] Rumsey C L, Biedron R T, Farassat F, et al. Ducted-Fan Engine Acoustic Predictions Using a Navier-Stokes Code[J]. Journal of Sound and Vibration, 1998, 213(4): 643-664. [107] Thomas R H, Gerhold C H, Farassat F, et, al. Far Field Noise of the 12-Inch Advanced Ducted Propeller Simulator[R]. AIAA 95-0722. [108] Parrett A V, Eversman W. Wave Envelop and Finite Element Approximations for Turbofan Noise Radiation in Flight[J]. AIAA Journal, 1986, 24: 753-760. [109] Roy I D, Eversman W, Meyer H D. Improved Finite Element Modeling of the Turbofan Inlet Radiation Problem[R]. NASA CR-1993-25952, 1993. [110] Tsuchiya Naoki, Nakamura Yoshiya, Yamagata Akihiro, et al. Fan Noise Prediction Using Unsteady CFD Analysis[R]. AIAA 2002-2491. [111] Polacsek C, Desbois-Lavergne F. Fan Interaction Noise Reduction Using a Wake Generator: Experiments and Computational Aeroacoustics[J]. Journal of Sound and Vibration, 2003, 265: 725-743. [112] Polacsek C, Burguburu S, Redonnet S, et al. Numerical Simulations of Fan Interaction Noise Using a Hybrid Approach[J]. AIAA Journal, 2006, 44(6): 1188-1196. [113] Grace S M, Sondak D L, Eversman W, et al. Hybrid Prediction of Fan Tonal Noise[R]. AIAA 2008-2992. [114] Weckmüeller C, Guerin S, Ashcroft G. CFD-CAA Coupling Applied to DLR UHBR-Fan: Comparison to Experimental Data[R]. AIAA 2009-3342. [115] Keisuke Tanigawa, Nobuhiko Yamasaki, Tsutomu Ooishi, et al. Improved Hybrid Prediction of Fan Noise[C]. Florida: 15th AIAA/CEAS Aeroacoustics Conference. [116] Guérin S, Holewa A. Fan Tonal Noise from Aircraft Aeroengines with Short Intake: A Study at Approach[J]. International Journal of Aeroacoustics, 2018, 17(6-8): 600-623. [117] Laban M, Kok J C, Brouwer H. CFD/CAA Analysis of UHBR Engine Tonal Noise[C]. Atlanta: 24th AIAA/CEAS Aeroacoustics Conference, 2018. [118] Garrec T L, Polacsek C, Chelius A, et al. Tone Noise Predictions of a Full-Scale UHBR Engine at Approach Condition with Inflow Distortion Effects[R]. AIAA 2019-2606. [119] Riou J, Lewy S, Heib S. Large Eddy Simuilation for Predicting Rotor-Stator Broadband Interaction Fan Noise[C]. Istanbul: 36th International Congress and Exposition on Noise Control Engineering, 2007. [120] Reboul G, Polacsek C, Lewy S, et al. Aeroacoustic Computation of Ducted-Fan Broadband Noise Using LES Data[J]. Journal of the Acoustical Society of America, 2008, 123(5). [121] Reboul G, Polacsek C, Lewy S, et al. Ducted-Fan Broadband Noise Simulations Using Unsteady or Averaged Data[C]. Shanghai: 37th International Congress and Exposition on Noise Control Engineering, 2008. [122] Laborderie J de, Moreau S, Berry A. Compressor Stage Broadband Noise Prediction Using a Large-Eddy Simulation and Comparisons with a Cascade Response Model[R]. AIAA 2013-2042. [123] Wang Meng, Moin Parviz. Computation of Trailing Edge Flow and Noise Using Large-Eddy Simulation[J]. AIAA Journal, 2000, 38: 2201-2209. [124] Manoha Eric, Troff Bruno, Sagaut Pierre. Trailing Edge Noise Prediction Using Large Eddy Simulation and Acoustic Analogy[R]. AIAA 98-1066. [125] Greschner B, Grilliat J, Jacob M C, et al. Measurements and Wall Modeled LES Simulation of Trailing Edge Noise Caused by Turbulent Boundary Layer[J]. International Journal of Aeroacoustics, 2010, (9): 329-355. [126] Lockard D P. A Comparison of Ffowcs Williams-Harkings Solvers for Airframe Noise Applications[R]. AIAA 2002-2580. [127] Wolf W R, Lele S K. Trailing Edge Noise Predictions Using Compressible LES and Acoustic Analogy[R]. AIAA 2011-2784. [128] Tucker P G. Computation of Unsteady Turbomachinery Flows: Part 2-LES and Hybrids[J]. Journal of Sound and Vibration, 2011, 47: 546-569. [129] Nallasamy M, Envia E. Computation of Rotor Wake Turbulence Noise[J]. Journal of Sound and Vibration, 2005, 282: 649-678. [130] Polacsek C, Clair V, Garrec T L, et al. Numerical Predictions of Turbulence/Cascade Interaction Noise Using Computational Aeroacoustics with a Stochastic Model[J]. AIAA Journal, 2015, 53(12): 3551-3565. [131] Guérin S, Kissnery C, Kajasaz B, et al. Noise Prediction of the ACAT1 Fan with a RANS-Informed Analytical Method: Success and Challenge[R]. AIAA 2019-2500. [132] Inoue M, Kuroumaru M. Structure of Tip Clearance Flow in an Isolated Axial Compressor Rotor[J]. Journal of Turbomachinery, 1989, 111(3): 250-256. [133] Storer J A, Cumpsty N A. Tip Leakage Flow in Axial Compressors[J]. Journal of Turbomachinery, 1991, 113: 252-259. [134] Lakshminarayana B, Zaccaria M, Marathe B. The Structure of Tip Clearance Flow in Axial Flow Compressors[J]. Journal of Turbomachinery, 1995, 117: 336-347. [135] Kameier F, Neise W. Experimental Study of Tip Clearance Losses and Noise in Axial Turbomachines and Their Reduction[J]. Journal of Turbomachinery, 1997, 119: 460-471. [136] Fukano T, Jang C M. Tip Clearance Noise of Axial Flow Fans Operating at Design and Off-Design Condition[J]. Journal of Sound and Vibration, 2004, 275: 1027-1050. [137] Hughes C E, Woodward R P, Podboy G G. Effect of Tip Clearance on Fan Noise and Aerodynamic Performance[R]. AIAA 2005-2875. [138] Corsini Alessandro, Rispoli Franco, Sheard A G. Aerodynamic Performance of Blade Tip End-Plates Designed for Low-Noise Operation in Axial Flow Fans[J]. Journal of Fluids Engineering, 2009, 131(8). [139] 王良锋, 风扇管道声模态识别的实验及数值模拟研究[D]. 西安: 西北工业大学, 2017. |
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