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亚声速射流的流场中存在着动能、热能、声能等多种形式能量的输运与转化,影响射流的稳定性和噪声辐射等特性,准确认识射流中各模态能量的输运特性是发展高效降噪措施的重要基础。基于拓展型亥姆霍兹分解流声分离方法,发展了基于流声分离的脉动能量方程,可有效分离脉动能量及能流矢量中涡、熵、声及非线性模态的贡献,为揭示流动近场的能量输运特性提供了分析工具。将该方程应用于射流马赫数0.9的亚声速射流,获得并分析了流声模态能量的空间分布特征和输运特性。研究发现:亚声速射流脉动能中的涡模态能量和熵模态能量分布于射流近场并向下游输运;声模态能量在势核外向远场辐射,在势核内则由束缚波携带传播至上游;多模态非线性相互作用相关的能量集中于射流尾迹区内,输运无显著方向性。In the near field of a subsonic jet, complex energy transport and transformation processes occur among kinetic, thermal, and acoustic energies, which play crucial roles in jet instability and noise radiation. Accurately characterizing the transport features of each energy component is essential for developing effective noise suppression technologies. Building upon Myers' [1991 J. Fluid Mech. 226 383] exact energy equation for total disturbances in arbitrary steady flow, the present study develops a modified energy equation based on hydro-acoustic mode decomposition to separate the contributions of vortical, entropic, and acoustic modes to the total disturbance energy. The methodology begins with the decomposition formulas for velocity, pressure, and density, following the hydro-acoustic mode decomposition method proposed by Han et al. [2023 Phys. Fluids 35 076107]. In Myers' energy equation framework, the disturbances of primitive variables (velocity, pressure, and density) are expressed as linear combinations of their vortical, entropic, and acoustic components. Through this formulation, vortical (entropic, acoustic) energy is defined as exclusively contributed by the corresponding mode's disturbances, while nonlinear energy is attributed to interactions among vortical, entropic, and acoustic components. This approach yields a modified energy equation capable of distinguishing the individual contributions of vortical, entropic, and acoustic modes to both total disturbance energy and energy flux, making it particularly suitable for analyzing energy transport characteristics in the near flow field. The developed equation is applied to analyze a Mach number 0.9 subsonic jet, revealing distinct spatial distributions and transport mechanisms of hydrodynamic and acoustic energies. The results demonstrate that vortical and entropic energies are predominantly concentrated in the near field, convecting downstream at approximately 0.8 times the jet velocity. In contrast, acoustic energy exhibits dual propagation characteristics: radiating outward to the far field through acoustic waves outside the potential core while propagating upstream via trapped waves within the potential core. The energy associated with multi-mode nonlinear interactions primarily concentrates in the jet wake, propagating without significant directivity. The total disturbance energy is predominantly contributed by vortical energy, while the acoustic energy accounting for only a minuscule fraction of the total disturbance energy, approximately on the order of 10-3 of the total. This refined analysis provides deeper insights into the complex energy dynamics in subsonic jets, offering valuable information for jet noise prediction and control strategies. The modified energy equation presents a robust framework for understanding and quantifying the intricate energy transport processes in jet flows.
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[1] Viswanathan K 2024 Int. J. Aeroacoust. 23 184
[2] Jordan P, Gervais Y 2008 Exp. Fluids 44 1
[3] Li X D, Xu X H, Gao J H, He J Y 2018 Acta Aerodyn. Sin., 36 398 (in Chinese)[李晓东, 徐希海, 高军辉, 何敬玉 2018 空气动力学学报 36 398]
[4] Chu B-T 1965 Acta Mech. 1 215
[5] Tam C K W, Viswanathan K, Ahuja K K, Panda J 2008 J. Fluid Mech. 615 253
[6] Tam C K W 2019 Philos. Trans. R. Soc. A 377 20190078
[7] Obrist D 2011 Phys. Fluids 23 024901
[8] Cavalieri A, Jordan P, Lesshafft L 2019 Appl. Mech. Rev. 71 020802
[9] Cavalieri A, Rodriguez D, Jordan P, Colonius T, Gervais Y 2013 J. Fluid Mech. 730 559
[10] Papamoschou D 2018 Int. J. Aeroacoust. 17 52
[11] Jordan P, Daviller G, Comte P 2013 J. Sound Vib. 332 3924
[12] Doak P 1989 J. Sound Vib. 131 67
[13] Liu Qilin, Lai Huanxin 2022 Phys. Fluids 34 045125
[14] Liu Q, Lai H. 2022 J. Eng. Thermophys., 43 3266 (in Chinese)[刘琪麟, 赖焕新 2022 工程热物理学报 43 3266]
[15] Unnikrishnan S, Gaitonde D V 2016 J. Fluid Mech. 800 387
[16] Myers M 1986 J. Sound Vib. 109 277
[17] Myers M K 1991 J. Fluid Mech. 226 383
[18] Han S, Li H, Luo Y, Wang Y, Ma R, Zhang S 2023 Phys. Fluids 35 076107
[19] Towne A, Dawson S, Brès G A, Lozano-Duran A, Saxton-Fox T, Parthasarathy A, Jones A R, Biler H, Yeh C, Patel H D, Taira K 2023 AIAA J. 61 2867
[20] Vreman A., 2004, Phys. Fluids, 16 3570.
[21] Brès G A, Jordan P, Jaunet V, Rallic M L, Cavalieri A V G, Towne A, Lele S K, Colonius T, Schmidt O T 2018, J. Fluid Mech., 851, 83
[22] Brès G A, Jordan P, Colonius T, Rallic M L, Jaunet V, Lele S K 2014, Proceedings of the Summer Program. Stanford, CA: Center for Turbulence Research, Stanford University, 2014, p221
[23] Freund J B. 1997, AIAA J. 35 740
[24] Mani A. 2012, J. Comput. Phys. 231 704
[25] Han S, Wang Y, Wu C, Luo Y, Li H 2024. Chin. J. Theor. Appl. Mech. 56 3142 (in Chinese)[韩帅斌, 王益民, 武从海, 罗勇, 李虎 2024 力学学报 56 3142]
[26] Mao F, Shi Y, Wu J 2010 Acta Mech. Sin. 26 355
[27] Wu J, Ma H, Zhou M 2006 Vorticity and Vortex Dynamics (Berlin: Springer) p341
[28] Sagaut P, Cambon C. 2008, Homogeneous turbulence dynamics (Cambridge: Cambridge University Press) p80
[29] Kovasznay L S G. 1953, J. Aeronaut. Sci, 20 657
[30] Chu B T, Kovásznay L S G 1958, J. Fluid Mech., 3 494
[31] Campos L 2007 Appl. Mech. Rev. 60 149
[32] Zaman K B M Q, Fagan A F, Upadhyay P 2022 J. Fluid Mech. 931 A30
[33] Schmidt O T, Towne A, Colonius T, Cavalieri A V G, Jordan P, Bres G A 2017 J. Fluid Mech. 825 1153
[34] Suzuki T, Colonius T 2006 J. Fluid Mech. 565 197
[35] Towne A, Cavalieri A V, Jordan P, Colonius T, Schmidt O, Jaunet V, Bres G A 2017 J. Fluid Mech. 825 1113
[36] Colonius T, Lele S K. 2004, Prog. Aerosp. Sci., 40 345
[37] Zhao K, Zhang P R, Yang M, Wang X N, Yu R K 2024. Acta Aerodyn. Sin. 42 15 (in Chinese)[赵鲲, 章荣平, 杨玫, 王勋年, 余荣科 2024 空气动力学学报 42 15]
[38] Wang Y, Ma R, Wu C, Luo Y, Zhang S 2021, Acta Phys. Sin. 70 99 (in Chinese) [王益民, 马瑞轩, 武从海, 罗勇, 张树海 2021 物理学报, 70 99]
[39] Ma R, Wang Y, Zhang S, Wu C, Wang X 2021, Acta Phys. Sin. 70 184 (in Chinese) [马瑞轩, 王益民, 张树海, 武从海, 王勋年 2021 物理学报, 70 184]
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